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Papers in English
Superconductivity Enhancement in thin Films of Niobium in Superconducting
Double-Barrier Structures
P. V. Komissinski and G. A. Ovsyannikov
We report the experimental results on the investigation of
superconducting double-barrier structures with niobium interlayer and Al2O3
barriers. The experimental results can be explained by an extreme enhancement of
superconductivity in the interlayer in accordance with the quasiparticle balance
model, where the energy dependence of the inelastic relaxation time of
quasiparticles with energy close to the superconducting gap is taken into
account.
Phys. Rev. B, v. 54, p. 13184 (1996).
Electrical and magnetic characteristics of YBCO thin films on CeO2
buffered Al2O3
substrates
T. Nurgaliev, G. Ovsyannikov, S. Miteva, A. Mashtakov, P. Komissinski, and
A. Spasov
Thin films of YBCO covered by protecting CeO2
overlayer were prepared on CeO2 buffered Al2O3
substrates and their magnetic characteristics were investigated at T>77 K using
contactless dc and ac magnetic techniques. The critical current density Js
measured at 77 K by different techniques was more or about 106
A/cm2: some difference in results was interpreted as due to the
peculiarities of the methods. A non-conventional methods was developed to
extract the Jc vs T dependence from the ac response signal parameters
and for the considered films it was found to be best fitted with a quadratic
function of the temperature. The Jc value decreased nearly two times
when perpendicular dc magnetic field B=150 mT was applied: the time dependence
of the trapped field was not pronounced at 77 K and it was less than 3 % for
7x103 s time interval.
Proceedings of the Third European Conference on Applied Superconductivity
(EUCAS’97), Twente, The Netherlands, Inst. Phys. Conf. Ser. No 158, v. 1, p. 109
(1997)
Comparison of high-pressure dc-sputtering and pulsed laser deposition of
superconducting YBa2Cu3Ox thin films
P. B. Mozhaev, P. V. Komissinski, N. P. Kukhta, A. Kuhle, G. A. Ovsyannikov,
J. L. Skov
Superconducting YBa2Cu3Ox
thin films were deposited on NdGaO3 (I IO) substrates using two
different techniques: dc sputtering at high oxygen pressure and pulsed laser
depositions. The structure, electrical properties and surface morphology of the
obtained films were compared. The superior crystal quality of dc-sputtered films
fabricated at the same temperature and at oxygen pressure of the same
range as for laser-deposited films can be explained by a lower deposition rate
providing time for recrystallization processes. The re-evaporation becomes
significant for dc sputtering at high deposition temperatures and results
in Ba-deficient films. The high mobility of atoms on the surface of the growing
film during laser deposition helps in the formation of smooth c-oriented areas
of the film.
J. of Supercond. v. 10, p. 221 (1997)
Improvement of the conducting parameters of YBa2CuOx
films grown on sapphire through the use of a strontium titanate buffer layer.
G. A. Ovsyannikov, A. D. Mashtakov, P. B. Mozhaev, P. V. Komissinski, Z.
G. Ivanov, P. Larsson
High-Tc superconducting films of YBa2Cu3Ox
on sapphire with an additional buffer layer of strontium titanate (actually,
on heterostructures (100)SrTiO3/(001)YBa2Cu3Ox/(100)CeO2/(1102)Al2O3)
are obtained by laser deposition, and their superconducting characteristics are
investigated. It is shown that buffering the sapphire by a strontium titanate
film can raise the critical temperature of the YBa2CuOx
films by two degrees and give a severalfold increase in the critical current
density.
Technical Physics Letters, v. 24, p. 676 (1998)
The influence of the top and the bottom grain boundaries on the current
transport in YBCO step-edge Josephson junction
F. Lombardi, Z. G. Ivanov, P. Komissinski, G. M. Fischer, P. Larsson and T.
Claeson
We have studied the electrical transport properties of the
grain boundaries (Gbs) formed at the top and at the bottom edges of YBa2Cu3O6-7
step-edge Josephson junctions, for different values of the step angle α .
the step-edged functions were fabricated on (100) LaAlO3 steps using
a tilted Ar ion milling. Due to the shadowing effect of the step, the middle and
the bottom part of the step edge junction were contacted by thin stripes. We
found that for α≈60o the top GB is
responsible for the weak link behaviour of our step-edge junctions. On less
steep steps, α≈45o, a series od
GBs with weak link properties wwere found to nucleate along the step profile. We
also correlated these results with the different microstructural properties of
the GBs formed on steps with different angles.
Applied Superconductivity v. 6, p. 437 (1998).
Tunable detection of radiation from HTSC Josephson junction arrays
K. Lee, I. Iguchi, K.Y. Constantinian
We have investigated the mutual phase interaction between a
single detector junction and a phase-locked three-junction array of high-Tc
Josephson junctions. The YBCO Josephson junctions were fabricated on a MgO
bicrystal substrate. We measured the radiation power of a Josephson-junction
array using an off-chip coupled to a radiometer and on-chip coupled to a single
junction from centimeter- to millimeter-wave ranges. The Josephson oscillation
power excited the resonant mode coupled to the coplanar microstrip loops. Clear
self-induced Shapiro steps were observed in the current–voltage curves of the
detector junction. The power transfer to the single detector junction was
estimated from the modulation of the Shapiro step height. The maximum detected
power level was about 7 nW at frequency 150–250 GHz.
Physica C, v. 320, pp. 65–70 (1999)
Current transport along the [001] axis of YBCO in low-temperature
superconductor-normal metal-high-temperature superconductor heterostructures
F. V. Komissinskii, G. A. Ovsyannikov, N. A. Tulina, V. V. Ryazanov
The electrophysical properties of heterojunctions several
microns in size, obtained by successive depopsition f the metal-oxide
high-temperature superconductor YBa2CuOx, a normal metal
Au, and the low-temperature superconductor Nb, were studied experimentally.
Current flows in the [001] direction of the epitaxial YBa2CuOx
film. It is shown, by comparing the experimental data with existing theoretical
calculations, that the experimentally realizable transmittances (D=10-5
- 10-6) of the YBa2CuOx normal metal boundary
the critical current of the entire heterostructure is low (of the order of the
fluctuation current) because of a sharp change in the amplitude of the potential
or the superconducting carriers at this boundary. the current voltage
characteristics of the heterostructure studied correspond to tunnel junctions
consisting of a superconductor with dx2-y2
type symmetry of the superconducting wave function and a normal metal.
JETP v. 89, p. 1160 (1999)
Fabrication and properties of high-Tc ramp
junctions with manganate barriers
M.Q. Huang, Z. G. Ivanov, P. V. Komissinski, and T. Claeson
We report on fabrication and characterization of YBa2Cu3O6-7
(YBCO) ramp junctions with a barrier of doped manganite, La0.67Sr0.33MnO3
(LSMO). Multilayers of YBCO and LSMO are epitaxially grown on (100) SrTiO3
substrates by on-axis pulsed laser ablation. The resistance and current-voltage
characteristics of the ramp junctions have been measured as a function of
barrier thickness, in the range of 10-30 mn, and of temperature. Junctions with
20 nm thick barriers had RSI-like current-voltage characteristics with a small
excess current. The critical current density and normal state resistance
of the junctions at 4.2 K were 5x103 A/cm2 and 300
Ω, respectively.
Physica C, v. 326-327, p. 79
(1999).
Single Flux Quantum Comparators for HTS ADS Converters
A. Yu. Kidiyarova-Shevchenko, D. E. Kirichenko, Z. Ivanov, P.
Komissinski, E. A. Stepancov, M. M. Khapaev, and T. Claeson
We have investigated different comparators for Flash and
S-D
high temperature superconducting ADCs designed
using three-layer HTS tri-crystal junction integrated circuit technology with
spread of the junction critical currents less than 10 % and features size
0.6 µm. Using the theoretical estimations for the bit error rate in RSFQ circuit
under the restrictions of the given technology, we have estimated working
temperature as T=62 K. At this temperature, the circuits were optimized in
order to achieve maximum performance of the related ADCs in terms of inhibit
bandwidth, resolution and operating margins. For design purposes, a novel method
was developed for inductance calculation with 3D magnetic field distribution in
multilayer superconducting technology and extraction of the inductance matrix of
the equivalent circuit.
Physica C, v.
326-327, p. 83 (1999).
High-Tc Ramp Josephson Junctions for Rapid Single Flux Quantum
Circuits
M. Q. Huang, P. V. Komissinski, P. B. Mozhaev, Z. G. Ivanov and
T. Claeson
Ramp-type Josephson junctions with YBCO superconducting
electrodes and PrBa2Cu2.6O6+δ
(PBBGCO) barriers were fabricated and
characterized. The YBCO ramp junctions with 25 mn-thick barriers of PBGCO showed
typical resistively-shunted-junction (RSJ)-like I-V behavior and 1σ spread of
less than 13 % in critical current density. Differential conductance-voltage
characteristics registered using a lock-in technique indicate that the resonant
tunneling via localized states in the barriers plays a dominant role in the
conduction process of the ramp junctions.
J. of Low Temp.
Phys. v. 117, p. 587 (1999).
Structural Studies of YBCO Ramp Josephson Junctions for
Rapid Single Flux Quantum Circuits
M. Gustafsson, E. Olsson, M. Q. Huang, P. V. Komissinski, P. B.
Mozhaev,
and Z. G. Ivanov
Ramp-type Josephson junctions with barrier layers of Ga doped PrBa2CuO7-δ
have been investigated using scanning and transmission electron microscopy. The
microstructures have been correlated to the ramp geometry. The junctions
exhibited low excess current. This is believed to be due to the uniform
thickness of barrier layer deposited on the ion-milled edges. The uniformity of
the barrier is presumed to be a result of the smooth rump, which promoted
uniform nucleation and epitaxial growth.
J. of Low Temp.
Phys. v. 117, p. 575 (1999).
Current transport mechanism in YBCO bicrystal junctions on sapphire.
G.A. Ovsyannikov, I.V. Borisenko, A.D. Mashtakov, K.Y. Constantinian
YBCO junctions were made on r-cut sapphire bicrystal substrates
in which the directions <1120> for both parts of the substrate have the
angles ±12° to the plane of the interface of electrodes. The junctions were
tested at dc and mm waves. The junctions with 5 µm width have high normal
resistance RN=10-20 W, IcRN=1-2
mV and tolerance of characteristic interface resistance around 30% on a chip. DC,
microwave and magnetic characteristics of the junctions have been investigated
experimentally. The sinusoidal superconducting current-phase relation and a
linear dependence of critical current density vs square root of the barrier
transparency was revealed. Experimental results are discussed in framework of
predictions for superconducting current transport via Andreev bound surface
states in bicrystal junction.
IOP Conf.Ser., No 167, pt. II, pp. 253-256 (2000)
YBa2Cu3Ox/CeO2/NdGaO3
epitaxial heterostructures at different substrate orientations.
I.K. Bdikin, I.M. Kotelyanskii, E.K. Raksha, A.D. Mashtakov, P.B. Mozhaev,
P.V. Komissinskii, G.A. Ovsyannikov
YBa2Cu3Ox/CeO2
epitaxial heterostructures were grown on NdGaO3 substrates with
surface orientation tilted from the (110) plane. Two types of epitaxial
relations were observed for CeO2 buffer layer, depending on
deposition technique and deviation angle of the substrate surface from the (110)
NdGaO3 plane. The YBa2Cu3Ox thin
films on the CeO2 buffer layer grow either oriented with c axis
normal to substrate plane, or following the orientation of the <100> axes of the
buffer layer. Observed changes in epitaxy can be explained with different film
formation mechanism at different deposition rates.
IOP Conf.Ser., No 167, pt. II, pp. 121-124 (2000)
MM wave Josephson radiation in High-Tc bicrystal junction arrays
K.Y. Constantinian, A.D. Mashtakov, G.A. Ovsyannikov, V.K. Kornev, A.V.
Arzumanov, N.A. Shcherbakov, M. Darula, J. Mygind, N.F. Pedersen
High-Tc Josephson junction arrays with coupling by
superconducting short-circuited (5 mm wide and 0.1
mm thick) coupled microstrip lines, provided dc bias in parallel, were
fabricated on bicrystal sapphire substrates for experimental investigation of
the phase-locking phenomenon. Josephson self radiation, emitted by the array was
measured by an external 90 GHz receiver for different applied dc magnetic fields.
The numerical simulation of array shows that strong interaction between
Josephson junctions and the standing waves within structure require small enough
damping a<10-3 per coupling section for
reduction of Josephson oscillation linewidth.
IOP Conf. Ser., No 167, pp. 717-720 (2000)
Substitutions in the Nd/Ba Cation Subsystem in Thin Films of the NdBa2Cu3Oy
High-Temperature Superconductor
P.B. Mozhaev, F.V. Komissinskii, Z.G. Ivanov, G.A. Ovsyannikov
Thin films of the Nd1+xBa2-xCu3Oy
high-Tc superconductor (NBCO) with different neodymium/barium ratios
have been obtained by laser ablative cosputtering of targets with different
elemental compositions. The films with excess neodymium (x>0) had a low
surface particle density and were rough, but their critical temperature
decreased with increasing x. On the contrary, barium-rich films (x<0)
exhibited independence of the superconducting properties of the film composition,
with an appreciable amount of particles observed on the surface. Substitution of
Ba for Nd in NBCO thin films is apparently impeded, so that excess barium
precipitates in the form of (Ba,Cu)Oz particles. The structure and
superconducting properties of NBCO reveal a strong dependence on the conditions
of film saturation by oxygen.
Physics of the Solid State, Vol. 42, No 9, pp. 1590-1595 (2000),
Translated from Fizika Tverdogo Tela, Vol. 42, No 9, pp. 1547-1552 (2000).
Particle formation on the YBCO thin film surface: effect of stoichiometry
and substrate material
P.B. Mozhaev, F. Ronnung, P.V. Komissinskii, Z.G. Ivanov, G.A. Ovsyannikov
Particle formation on the YBa2Cu3O7-x
(YBCO) thin film surface deposited by laser ablation was studied. Ablation of a
stoichiometric YBCO target results in Ba-deficient films, probably due to Ba
scattering in oxygen atmosphere. Partial melting of the target surface during
ablation provided additional Ba flow and resulted in smooth films. Surface
quality of the YBCO film with improved element composition depends on lattice
mismatch between the growing film and the substrate. Increase of deposition
temperature over some threshold level, specific for each tested substrate
material, results in particle appearance on the film surface even in the films
with improved element composition. Chemical interaction, caused by oxygen
depletion of the substrate surface, can be the reason for this effect.
Physica C, v. 336, pp. 93–101 (2000)
Orientation relations and twinning in heterostructures YBa2Cu3Ox//NdGaO3
and YBa2Cu3Ox//CeO2//Al2O3
I.K. Bdikin, A.D. Mashtakov, P.B. Mozhaev, G.A. Ovsyannikov
Epitaxial YBa2Cu3Ox (YBCO)
thin films on (110) NdGaO3 and (100)CeO2//(1102)Al2O3
substrates were studied with X-ray diffraction methods, orientation features of
film twinning were determined. Films on both substrates were mainly c-oriented
with c=11.67 A. Orthorhombic structure of NdGaO3 results in
increase of the angle between (110) and (110) twinning planes in YBCO
films to 90.20° and in difference in volume of two twin domain systems. About
60% of YBCO film on CeO2//Al2O3 substrates show
no twinning. The lattice direction [1102] of the Al2O3
substrate and [100] of the CeO2 film were inclined by 0.15°; this
inclination can result from high lattice mismatch between CeO2 film
and Al2O3 substrate. The [001] direction of the YBCO film
was inclined to [1102] Al2O3 direction only by
0.06°. The spread of in-substrate-plane misorientation in CeO2 film
of 1.65° was also higher than that of the YBCO film (1.22°).
Physica C, v. 334, pp. 168–174 (2000)
Electron transport in high-Tc superconducting grain boundary
junctions
G.A. Ovsyannikov, I.V. Borisenko, K.Y. Constantinian
The current state and the prospects of the application of
high-Tc superconducting grain boundary Josephson junctions in
microwave electronics devices are given. It is approached by sketching the
typical fabrication technique of the junction. Josephson bicrystal junctions on
sapphire substrate are considered in detail. The results of dc microwave and
magnetic measurements of YBCO bicrystal junctions on r-cut sapphire are
presented. The junctions with high resistance 10-20 W
and IcRN=1-2 mV and tolerance of RNS around 30%
on the chip allow to create microwave circuits with low integration (up to 10
junctions on chip). The microwave dynamics of the junction with superconducting
current-phase relation fits with sinf relation better
than 5%, that clearly indicates the tunnel conductivity between two YBCO
electrodes. It was found that critical current density depends on the square
root of interface transparency in accordance with the prediction of
superconducting current transport via Andreev's bound surface states. The
specific properties of current transport in high-Tc grain boundary
junctions with taking into account d-wave type of gap order in high-Tc
superconductor are discussed.
Vacuum, v. 58, pp. 149-157 (2000)
Arrays of Josephson Junctions Coupled by Distributed Circuits
V.K. Kornev, N.A. Shcherbakov, A.V. Arzumanov, P.B. Mozhaev, A.D. Mashtakov,
K.Y. Constantinian, G.A. Ovsyannikov
Both the linewidth reduction and the gain in output power have
been analyzed for Josephson-junction arrays with distributed coupling circuits.
Different ways of Josephson junction connection to the distributed circuits, as
well as both the nonlinear interaction effect and the crucial role of high
frequency losses have been studied. It has been found that the contradictory
requirements to the junctions as nonlinear active elements on (i) low wave
reflection and (ii) high total power produced can be fulfilled by an increase in
number of Josephson junctions with a proper impedance value. The first condition
is necessary to provide the most reduction in the linewidth, and the second one
is needed to compensate for the power output. An array of the biased in parallel
bi-crystal Josephson HTSC junctions coupled by microstrip circuit has been
fabricated and preliminary tested.
Presented on the Applied Superconductivity Conference '2000 (2000)
Superconducting Current - Phase Dependence in Josephson YBCO Bicrystal
Junctions on Sapphire
I.V. Borisenko, G.A. Ovsyannikov, K.Y. Constantinian, E.A. Stepantsov
The deviation of superconducting current-phase relation (CPR)
in Josephson junction (JJ) from sinusoidal one is very important for the
application of JJ in electronics. The dependencies of the amplitudes of the
harmonic and subharmonic Shapiro steps were used to study CPR of YBCO JJ on a
bicrystal sapphire substrate. It is shown that for a symmetric set of the
transport current across the symmetric bicrystal junction, the CPR is close to
sinusoidal one that differs from the theoretical predictions based on d-type of
superconducting wave function in the electrodes. The divergence from symmetry in
the transport current across JJ causes the CPR to deviate from sinusoidal type
and the deviation increases with increasing degree of asymmetry. This change in
the CPR is discussed within the model, which takes into account the formation of
coupled Andreev states in JJ of superconductors with a d-type of superconducting
wave function.
Presented on the Applied Superconductivity Conference '2000 (2000)
Current transport in Au/YBCO junctions in c-axis and tilted
directions of YBa2Cu3Ox thin films
P. Komissinski and G. A. Ovsyannikov
We report on the fabrication technique and investigation of current
properties of Au/YBa2Cu3Ox junctions. The
junctions were processed in epitaxial YBa2Cu3Ox
(YCBO) thin films grown by laser ablation. (001) LaAlO3 and (120)
NdGaO3 substrates were used to grow correspondingly (001)-oriented
and tilted YBaCO films. Current-voltage characteristics, Z-V-curves, and the
dependencies of the differential resistance on the applied voltage, Rd(V), were
measured and the anisotropy of the current transport in these junctions was
studied.
Proceedings of the Fourth European Conference on Applied Superconductivity
(EUCAS’99), Sitges, Spain, Inst. Phys. Conf. Ser. No 167, v. 2, p. 233 (2000).
S-D
modulator for TS ADC based on the ramp-type Jusephson junctions
A. Yu. Kidiyarova-Shevchenko, M. Huang, P. Komissinski, Z. Ivanov, and T.
Claeson
An all high-Tc modulator for Σ-Δ
analog-to-digital converters (ADC) was optimized with parameters determined
by a ramp type Josephson junction technology having a critical current
spread less than 13% and using four superconducting layers. Equivalent
circuit inductances were extracted from layouts with the help of a new
multilayer 3D-MLSI software package. The resulting performance of the ADC is
analyzed in detail and possible improvements are discussed.
Proceedings of the Fourth European Conference on Applied Superconductivity
(EUCAS’99), Sitges, Spain, Inst. Phys. Conf. Ser. No 167, v. 2, p. 737
(2000).
Spectral characteristics of mm wave radiation emitted by HTSC Josephson-junction arrays
G. A. Ovsyannikov, A.D. Mashtakov, K. Y. Constantinian, A. V. Arzumanov, N. A. Shcherbakov, M. Darula, J. Mygind, N. F. Pedersen
Abstract 5EF04, ASC2000.
YBCO Josephson junctions on bicrstal sapphire substrates
for submm wave application
K. Y. Constantinian, G. A. Ovsyannikov, I. V. Borisenko, A. D. Mashtakov, N. G. Pogosyan, A. A. Hakhoumian, J. Mygind, N. F. Pedersen
Abstract 2EC02 ASC2000, p. , 2000.
Surface Resistance of the Y-Ba-Cu-O Thin Films at Sub-MM Wave Frequencies
Arsen Hakhoumian, Nubar Pogosyan, Tigran Zakaryan, Gennady Ovsyannikov, Karen Constantinian
Abstract 4MA06, ASC2000.
Investigation of current carrying and microwave characteritics of double-side YBCO thin films
T. Nurgaliev, T. Donchev, V. Tsaneva, S.Miteva, R. Chakalov, A. Spasov, A. Mashtakov, G. Ovsyannikov
Physica B, 284-288, p.957-958, (2000).
Re/Ba interchange in the ReBCO thin films and oxygenation after deposition
P.B. Mozhaev, G.A. Ovsyannikov, P.V. Komissinskii, Z.G. Ivanov, T. Claeson, I.K. Bdikin
Applied Superconductivity Conference 2000, Abstract, USA, p.193, 2000.
Epitaxial growth of YBa2Cu3Ox/CeO2/NdGaO3 heterostructures at different substrate orientations
I.K. Bdikin, I.M. Kotelyanskii, E.K. Raksha, A.D. Mashtakov, P.B. Mozhaev, P.V. Komissinskii, G.A. Ovsyannikov
Applied Superconductivity Conference 2000.
Electon transport in c-axis and tilted c-axis YBa2Cu3Ox/normal metal contacts
P. Komissinski, Z. Ivanov, I. Bdikin, P. Mozhaev, G. Ovsyannikov
Presented on Applied Superconductivity Conference 2000 (ASC 2000), Virginia, USA, Abstract book p. 193 (2000).
Temperature Behavior of Electron Transport in Normal-Metal-HTSC
Heterojunctions
F. V. Komissinskii, G. A. Ovsyannikov, and Z. G. Ivanov
Current transport in micron-sized normal-metal - high-temperature
superconductor heterojunctions (Au/YBa2Cu3O6+x)
was studied for two crystallographic orientations of YBCO films. It is shown
that depending of the transport-current flow direction relative to the
crystallographic axes of the YBCO film, the electronic transport properties
of Au/YBCO heterojunctions with highly transparent boundaries change from
quasi-tunneling (along the YBCO c axis) to close-to-Ohmic (in the
directions lying in the YBCO basal plane).
Physics of the Solid State v. 43, p. 801 (2001)
Observation of the Second Harmonic in the Phase Dependence of a Superconducting
Current in Nb/Au/YBCO Heterojunctions
F. V. Komissinskii, G. A. Ovsyannikov, E. Il’ichev, and Z. Ivanov
The second harmonic in the dependence of a superconducting current on the phase
difference of superconducting wave functions of the electrodes was observed
experimentally in Nb/Au/(001)YBa2Cu3Ox
heterojunctions. Possible reasons for its appearance were discussed within the
framework of a mixed (d ± s) symmetry order parameter of YBa2Cu3Ox
.
Sov. Phys. JETP Lett. v. 73, p. 361 (2001)
Small Scale Integrated Technology for HTS RSFQ Circuits
M.Huang, P. V. Komissinski, A. Yu. Kidiyarova-Shevchenko, M. Gustafsson, E.
Olsson, B. Högberg, Z. Ivanov, and T. Claeson
A technology for fabrication of YBCO ramp junctions on a superconducting ground
plane is developed and evaluated. The technology is based on a two-layer, S-I,
structure or on a four-layer, S-I-S-I , structure grown in situ with YBCO
superconductor and with multilayer insulator of PBCO/STO/PBCO. Rumps for
junctions, via connections and crossovers are formed by Ar ion milling under
rotation and the ramp angle is less than 30° for
all directions. A 20-25 nm thick Ga-doped PBCO was used as a barrier for
Josephson junctions. One additional YBCO layer, for junction top electrodes and
wiring , is deposited and patterned. Surface roughness of multilayers is
characterized by AFM and is related to the junction parameters. Transport
properties of junctions, via connections and crossovers are evaluated.
IEEE Trans. on Appl. Supercond., v. 11, p. 558 (2001).
Observation of the second harmonic in superconducting current-phase relation of
Nb/Au/(001)YBa2Cu3Ox heterojunctions
P. V. Komissinski, E. Il’ichev, G. A. Ovsyannikov, S. A. Kovtonyuk, M. Grajcar,
R. Hlubina, Z. Ivanov, Y. Tanaka, N. Yoshida, and S. Kashiwaya
The superconducting current-phase relation (CPR) of Nb/Au/(001)YBa2Cu3Ox
heterojunctions prepared on epitaxial c-axis oriented YBa2Cu3Ox
thin films has been measured in a single-junction interferometer. For the first
time, the second harmonic of the CPR of such junctions has been observed. The
appearance of the second harmonic and the relative sign of the first and
second harmonics of the CPR can be explained assuming, that the macroscopic
pairing symmetry of our YBa2Cu3Ox thin films is
of the d + s type.
European Physics Letters 2001, in press.
Submicron YBACuO ramp Josephson junctions
P. Komissinski, B. Högberg, A. Tzalenchuk, Z. Ivanov, and T. Claeson
Submicron YBa2Cu3Ox/PrBa2Cu2.6Ga0.4Ox/YBa2Cu3Ox
ramp-type Josephson junctions were fabricated and tested. The submicron bridges
in the top electrode were patterned by e-beam lithography and Ar ion milling
through an amorphous carbon (a-C) mask. Junctions with width ranging from
0.2 to 8 µm and oriented along different
crystal directions of YBa2Cu30x have been
produced. Current-voltage characteristics show a behavior consistent with the
resistively shunted junction model with small excess current. Junction critical
current densities of about 10 kA/cm2 and characteristic voltages up
to 6mV were measured at 4.2 K for the submicron junctions. Junctions along
different crystal orientations showed different characteristics suggesting an
influence from the d-wave order parameter.
submitted to Applied Physics Letters, 2001.
Experimental study of noise and Josephson oscillation linewidths in bicrystal YBCO junctions
K. Y. Constantinian, G.A. Ovsyannikov, I. V. Borisenko, N. G. Pogosyan,A. A. Hakhoumian, J. Mygind, N. F. Pedersen
International Superconducting Electronics Conference, Japan, Extended absracts, p.205-206, .2001
Observation of voltage-tunable submm wave response from YBCO Josephson device, operating in self-pumping mode
K Y. Constantinian, G.A. Ovsyannikov, I. V. Borisenko, P. Yagoubov
8th International Superconducting Electronics Conference, Japan, Extended absracts, p.79-80, 2001; Supercond. Sci. Technology, 14, 1005-1008, 2001
Temperature dependence of submm wave detector response from YBCO Josephson junction on bicrystal sapphire substrate
K Y. Constantinian, G.A. Ovsyannikov, I. V. Borisenko, P. Yagoubov
International Superconducting Electronics Conference, Japan, Extended absracts, p.511-512, 2001
High-Tc Josephson-Junction Arrays with Distributed Coupling Circuits
Victor K. Kornev, Nikita A. Shcherbakov, Peter B. Mozhaev, Igor V. Borisenko, Karen Y. Constantinian, Gennady. A. Ovsyannikov
International Superconducting Electronics Conference, Japan, Extended absracts, p.209-210, 2001
Low voltage excess noise and shot noise in YBCO bicrystal junctions
K. Y. Constantinian, G. A. Ovsyannikov, I. V. Borisenko
International symposium on Superconducting Device Physics, Tokyo, 2001, report Ja-4; Physica C, 367, 276-279, 2002
Voltage-tunable YBCO Josephson mixer, operating in self-pumping mode at 750-970 GHz
K.Y. Constantinian, G.A. Ovsyannikov, I.V. Borisenko, P. Yagoubov
presented at EUCAS2001; Physica C 372-376, p. 420-422, 2002
Experimental study of submm wave response and noise of bicrystal YBCO Josephson junctions
K.Y. Constantinian, G.A. Ovsyannikov, Yu. V. Kislinskii I.V. Borisenko,N.G. Pogosyan, A. A. Hakhoumian, J. Mygind and N. F. Pedersen
5th European Conf. on. Appl. Superconductivity, Abstracts, p.111, 2001; Supercond. Sci. Technology, 14, 1035-1039, 2001
Influence of thermal fluctuation on sensitivy of submm wave signal detection by bicrystal YBCO Josephson junctions
Karen Constantinian, Gennady Ovsyannikov, Yulii Kislinskii, IgorBorisenko
presented at EUCAS-2001
Pi – Interferometer Dynamics
V.K. Kornev, I.I. Soloviev, G.A.Ovsyannikov*, P.B. Mozhaev*
presented at EUCAS-2001
Dynamics of Superconducting Interferometers Containing pi-Junctions
V.K. Kornev, I.I. Soloviev, G.A.Ovsyannikov, P.B. Mozhaev, N.F. Pedersen
International workshop on “Superconducting nano-electronics devices”, Italy, 2001
Superconducting current-phase dependence in high-Tc symmetrical bicrystal junctions
Gennady A. Ovsyannikov, Igor V. Borisenko, Peter B. Mozhaev, Karen I. Constantinian
International workshop on “Superconducting nano-electronics devices”, Italy, 2001
High-temperature superconducting bi-crystal Josephson junctions with asymmetric current biasing
P.B. Mozhaev, G.A. Ovsyannikov, E.G. Ovsyannikova, I.V. Borisenko
5th European Conf. on. Appl. Superconductivity, Abstracts, p.95, 2001
Bicrystal Josephson –junction arrays coupled by distributed circuits
V.K. Kornev, N.A. Shcherbacov, I.V. Borisenko, G.A. Ovsyannikov, K.Y. Constantinian, P.B. Mozhaev
5th European Conf. on. Appl. Superconductivity, Abstracts,p.118, 2001
Dynamics of some pi-junction interferometers
V.K. Kornev, N.F. Pedersen, A.V. Arzumanov, P.B. Mozhaev, N.A. Shcherbacov
5th European Conf. on. Appl. Superconductivity, Abstracts, p.122, 2001
Twinning in YBCO films on substrates of different materials and at different orientation
P.B. Mozhaev, I.K. Bdikin, P.V. Komissinskii, G.A. Ovsyannikov
5th European Conf. on. Appl. Superconductivity, Abstracts, p.237, 2001
High-Tc Josephson-junction arrays with distributed coupling circuit
V.K. Kornev, N.A. Shcherbacov, P.B. Mozhaev, I.V. Borisenko, K.Y. Constantinian, G.A. Ovsyannikov
8th Int. Superconductive Electronics Conf., extended abstracts, p.209, 2001
Pi-junction circuit dynamics
V.K. Kornev, I.I. Soloviev, P.B. Mozhaev, E.G. Ovsyannikova, I.V. Borisenko, G.A. Ovsyannikov, N.F. Pedersen
8th Int. Superconductive Electronics Conf., extended abstracts, p.561, 2001
Interection of YBCO bicrystal junctin with electromagnetic surrounding
I.V. Borisenko, G.A. Ovsyannikov, K.Y. Constantinian
5th European Conf. on. Appl. Superconductivity, Abstracts, p.111, 2001
Arrays of Josephson junctions coupled by distributed circuits
V K. Kornev, N.A. Shcherbakov, A. V. Arzumanov, P. B Mozhaev, K. Y. Constantinian, A. D. Mashtakov, G. A. Ovsyannikov
IEEE Trans. on Appl. Superconductivity, 11, 2001, pp. 1227-1230
Superconducting Current-Phase Relation of Nb/Au/(001)YBCO heterojunctions
P.V. Komissinski, Z.G. Ivanov, E. Il’ichev, G.A. Ovsyannikov, M. Graicar, R.Hlubina
Physics and Applications of Superconducting Quantum Interference (SQUID 2001), Sweden, 2001, Book of Abstracts p.41; Physica C v. 368, pp. 271-275 (2002)
Pi-Interferometer Dynamics
V.K. Kornev, I.I. Soloviev, G.A. Ovsyannikov, P.B. Mozhaev, N.F. Pedersen
Physics and Applications of Superconducting Quantum Interference (SQUID 2001), Sweden, 2001, Book of Abstracts p.53
Superconducting Current-Phase Dependence in High-Tc Symmetrical Bicrystal Junctions
I.V. Borisenko, G.A. Ovsyannikov, P.B. Mozhaev, G.A. Ovsyannikov, K.Y. Constantinian
Physics and Applications of Superconducting Quantum Interference (SQUID 2001), Sweden, 2001, Book of Abstracts p.54
Growth and domain structure of YBCO thin films and YBCO/CeO2 heterostructures on tilted NGO substrates
I.K. Bdikin, P.B. Mozhaev, G.A. Ovsyannikov, P.V. Komissinski, I.M. Kotelyanskii
Physica C377, 26-35, 2002
Superconducting current-phase relation in high-Tc symmetrical bicrystal junction
I.V. Borisenko, P.B. Mozhaev, G.A. Ovsyannikov, K.Y. Constantinian, E.A. Stepantsov
Physica C, 3678, 328-331, 2002
Submicron YBaCuO ramp Josephson junctions
P. Komissinski, B. Högberg, A. Tzalenchuk, Z. Ivanov, and T. Claeson
Applied Physics Letters v. 80, N.6, pp.1022-24 (2002)
Observation of the second harmonic in superconducting current-phase relation of Nb/Au/(001)YBa2Cu3Ox heterojunctions
P. V. Komissinski, E. Il’ichev, G. A. Ovsyannikov, S. A. Kovtonyuk, M. Grajcar, R. Hlubina, Z. Ivanov, Y. Tanaka, N. Yoshida, and S. Kashiwaya
European Physics Letters v. 57, N.4, pp. 585-591, 2002
Submillimeter wave signal detection by bicrystal YBCO Josephson junctions at liquid nitrogen temperatures
Yu.V. Kislinskii, K.Y. Constantinian, I.V. Borisenko, G.A. Ovsyannikov, P. Yagoubov
Physica C 372-376, p.436-439, 2002
Bicrystal pi interferometers
Kornev V.K., Ovsyannikov I.G. A., Mozhaev P.B., Borisenko I.V., and Pedersen N.F.
Physica C 368, pp. 332-336 (2002)
Andreev States and Josephson Effect in Superconducting Heterojunctions on thin YBCO films
P.V.Komissinski, G.A. Ovsyannikov, Yu.V. Kislinski, I.M. Kotelyanski, Z.G. Ivanov
Experimental and Theoretical Physics, 95, N6, 1074-1084, 2002
Superconducting current–phase relation and Andreev bound states in Josephson Nb/Au/YBCO heterojunctions
G.A. Ovsyannikov, P.V. Komissinski, Yu.V. Kislinski, Z.G. Ivanov
Modern Physics Letters B, 17, N10-12, 569-578, 2003
The 0 and pi contact array model of bicrystal junctions and interferometers
Victor K. Kornev, Igor I. Soloviev, Nikolai V. Klenov, Niels F. Pedersen, Igor V. Borisenko Peter B. Mozhaev, Gennady A. Ovsyannikov
IEEE Transaction on Applied Superconductivity, June 2003, vol. 13, No. 2. p. 825-828
Josephson Effect in Superconducting Heterojunctions on thin YBCO films
G.A. Ovsyannikov, P.V.Komissinski, E. Il’ichev, Yu.V. Kislinski, Z.G. Ivanov
IEEE Tr. On Appl. Superconductivity, v.13, N2, 881-884, 2003
Shot noise of YBCO bicrystal Josephson junctions
K Y. Constantinian, G.A. Ovsyannikov, I. V. Borisenko, J. Mygind, N.F. Pedersen
IEEE Tr. On Applied Supercondutivity, v.13, N2, 610-613, 2003
Dc SQUID Behavior Resulting from no Sinusoidal Current-Phase Relation of Bicrystal Junctions
V.K, Kornev, N.V. Klenov I. V. Borisenko, G. A. Ovsyannikov
European Applied Superconductivity Conference (EUCAS’03), Italy, September 2003. Abstract p.146; Inst. Physics Conf. Ser. No 169, IOP Publishing Ltd, 2004, to be published
Josephson dynamics of [100] tilted YBCO bicrystal junctions on NdGaO3
G. A. Ovsyannikov, I.V. Borisenko, I.M. Kotelyanski, Yu. V. Kislinskii, P. V. Komissinski
European Applied Superconductivity Conference (EUCAS’03), Italy, September 2003. Abstract p.167
Shot noise in YBCO bicrystals and hybrid heterostruvtures
K. Y. Constantinian, G. A. Ovsyannikov, P. V. Komissinski, I.V. Borisenko
European Applied Superconductivity Conference (EUCAS’03), Italy, September 2003. Abstract p.211
Thin film Nb/Au/YBCO Superconducting Heterojunctions
P. V. Komissinski, K.Y. Constantinian, Yu. V. Kislinskii, G. A. Ovsyannikov, Z.G. Ivanov
European Applied Superconductivity Conference (EUCAS’03), Italy, September 2003. Abstract p.212
Andreev reflection in superconducting cuprate nanostructures: hetero- and bicrystal junctions
G. A. Ovsyannikov , P. V. Komissinski, I.V. Borisenko
European science foundation summer school on superconductivity. Crete, Greece September 20 - 27 ( 2003 ). Abstract p.102
Non-equilibrium shot noise in YBaCuO Josephson junctions on symmetric bicrystal substrates
K. Y. Constantinian, I.V. Borisenko, Y.V. Kislinskii, M. I. Bukharov, G. A. Ovsyannikov
presentation at International conference on superconducting electronics, Sydney, Australia, June 2003.Abstract p.Otu3
The Growth and Conductivity of CaCuO2 epitaxial thin films
G.A. Ovsyannikov, S.A. Denisuk, Z. Ivanov, T. Claeson
“7th International Conference on Materials and Mechanisms of Superconductivity and High Temperature Superconductors”, Rio de Janeiro, Brazil, May 2003. p.165, Physica C,v408-410, p.616-617, 2004
Near-field millimeter-wave Measerement of HTSC Film Surface Resistance
A. Hakhoumian, N. Pogosyan, T. Zakaryan, D. Bagdasaryan, G. Ovsyannikov, K. Constantinian
“7th International Conference on Materials and Mechanisms of Superconductivity and High Temperature Superconductors”, Rio de Janeiro, Brazil, May 2003. p.256
Josephson bicrystal junctions on sapphire substrates for submm waves receiver
I.V. Borisenko, K. Y. Constantinian, Y.V. Kislinski, G. A. Ovsyannikov, A. A. Hakhoumian, N. G. Pogosyan
Submitted to the fifthe International Kharkov symposium on Physics and engineering of microwaves, mollimeter and submillimetere waves, Kharkov, Ukrane, 2004
Josephson bicrystal junctions on sapphire substrates for THz frequency applications
K.Y. Constantinian, G.A. Ovsyannikov, I.V. Borisenko, Y.V. Kislinski, A.A. Hakoumian, N.G. Pogosyan
8th Symposium on High-Temparature Superconductors in High-Frequency Fields, Spain, 2004, p.55
Bandwidth and noise of submm wave detector on cuprate Josephson bicrystal junctions on sapphire substrates
G. A. Ovsyannikov, I.V. Borisenko, K. Y. Constantinian, Y.V. Kislinski, A. A. Hakhoumian, N. G. Pogosyan, T. Zakaryan, N.F. Pedersen, J. Mygind, N. Uzunoglu, E. Karagianni
Applied Superconductivity conference, USA, 2004
Size dependence of Josephson effect in hybrid oxide superconducting heterostructure
G.A. Ovsyannikov, P.V. Komissinski, Y.Y Kislinskii, I.V. Borisenko I.V.Constantinian, V.K. Kornev, T.Yu. Karminskaya
Applied Superconductivity conference, USA, 2004
Josephson dynamics of [100] tilted YBCO bicrystal junctions on NdGaO3
I.V. Borisenko, I.M. Kotelyanski, P. V. Komissinski, A.V. Shadrin, G. A. Ovsyannikov
Applied Superconductivity conference, USA, 2004
The Growth and Conductivity of Infinite Layer Cuprate Oxide Thin Films
G.A. Ovsyannikov, S.A. Denisuk, I.K. Bdikin
1st Topical Meeting Properties of Ultrathin oxide films , Italy 2004 p. 43
Current-Phase Relation and Noise in Hybrid Nb/Au/YBCO Heterojunctions
G.A. Ovsyannikov, P.V. Komissinskii, Y.V. Kislinski, K.Y. Constantinian
The Joint International Workshop on Nanostructured Superconductors: From fundamentals to application, Germany, May 2004 p.28
Josephson Parameters of Bicrystal Junctions of a New Type Based on Metal Oxide Semiconductors
I. V. Borisenko, A. V. Shadrin, G. A. Ovsyannikov, I. M. Kotelyanskii, and F. V. Komissinski
We have studied symmetric bicrystal Josephson junctions of a new type based on metal oxide superconductors in which the base planes are misoriented relative to the [100] direction by an angle within 22°–28°. These junctions exhibit record high values of the critical parameters at T=77 K: the critical current density reaches IC=(2–5)×105 A/cm2 and the characteristic voltage is VC=ICRN=0.6–0.9 mV. The properties of the new junctions have been determined for the first time under the influence of monochromatic microwave radiation in the millimeter wavelength range and have been studied as functions of the magnetic field and temperature. The observed dependences of the critical current and the Shapiro step height on the electromagnetic field amplitude agree well with the theoretical predictions according to the resistive shunted junction model of the Josephson junction. The new junctions can be used in real superconducting devices operating at liquid nitrogen temperatures.
Technical Physics Letters, Vol. 31, No. 4, 2005, pp. 332–335
Metal Oxide Bicrystal Josephson Junctions of a New Type with High Critical Parameters
I. M. Kotelyanskii, I. V. Borisenko, A. V. Shadrin, G. A. Ovsyannikov,V. A. Luzanov, and F. V. Komissinskii
The film bicrystal Josephson junctions of a new type based on a metal oxide high-Tc superconductor of the YBa2Cu3O7–x (YBCO) system are suggested and studied. In junctions of the new type, in contrast to the known ones, the working surfaces situated on the opposite sides of the bicrystal interface have different crystal orientations: one is (001)YBCO and the other is rotated (misoriented) relative to it by an asymmetric bicrystal angle around a certain axis lying in the substrate plane. The main electrical and dynamic (microwave) characteristics have been determined for junctions of the new type based on NdGaO3 bicrystal substrates with the misorientation angle varying from 13 to 28°. These junctions exhibit high values of the critical parameters at T=77 K, including the critical current density IC=(2–5)×105 A/cm2 and the characteristic voltage VC=ICRN=0.6–0.9 mV. Advantages of the bicrystal Josephson junctions of the new type over the known junctions are considered.
Technical Physics Letters, Vol. 31, No. 3, 2005, pp. 189–192
Characterization and Dynamics of [100]-Tilted Y-B-C-O Bicrystal Junctions on NdGaO3
Igor V. Borisenko, Iosif M. Kotelyanski, Anton V. Shadrin, Philippe V. Komissinski, and Gennady A. Ovsyannikov
We report on the fabrication technique and electrical properties of Basal Plane Tilted YBa2Cu3O7-x (YBCO) superconducting bicrystal Josephson Junctions (BTJ). In order to form the grain boundary in BTJ we apply an inclination of the (001) YBCO basal planes around the direction of {100} YBCO in contrast to the common In-Plane Tilted bicrystal Josephson Junctions (ITJ) where misorientation of the crystallographic axes in the ab-plane of YBCO has been used. Symmetric and asymmetric junctions were fabricated on bicrystal NdGaO3 substrates 13–28 tilted from (110) NdGaO3. DC and RF properties of the BTJ were investigates at temperatures 4.2–77 K, in magnetic fields up to 100 G, and under influence of electromagnetic radiation of 56 GHz frequency. The experimental dependences of critical current and Shapiro steps from RF current fit the Resistive Shunted model of Josephson junctions (RSJ-model). At T = 77 K the BTJ reveal critical current density jC = 0.2-0.5 MA/cm2 and characteristic voltage VC = ICRN = 0.6-0.9 mV, that makes the junctions promising candidate for practical electronic devices.
IEEE Transactions on Applied Superconductivity, Vol. 15, No. 2, June 2005, p.165-168
Bandwidth and Noise of SubmillimeterWave Cuprate Bicrystal Josephson Junction Detectors
Gennady A. Ovsyannikov, Igor V. Borisenko, Karen Y. Constantinian, Yulii V. Kislinski, Arsen A. Hakhoumian, Nubar G. Pogosyan, Tigran Zakaryan, Niels F. Pedersen, Jesper Mygind, Nikolaos Uzunoglu, and Evangelia Karagianni
Detectors made from superconducting cuprate YBa2Cu3Ox bicrystal Josephson junctions (BJJs) on sapphire and NdGaO3 substrates have been fabricated and characterized in the frequency band 200–900 GHz. Junctions on sapphire substrates had a normal state resistance RN~15-60 W , and product ICRN up to 2.5 mV at T= 42 K. Junctions on NdGaO3 substrates had lower RN = 1-5 W and ICRN = 04–0.9 mV at = 77K. Three types of detecting devices have been investigated in both the broadband and the frequency-selective detection modes. One type was patterned with log-periodic antenna, and two others with Pt-metal double-slot antenna designed for a central frequency f = 300 GHz and f = 400 GHz, respectively. Measurements at f = 320 GHz of the reception bandwidth df for a device with double-slot antenna gave a quality factor Q = f/df ~ 10. A low-noise cooled 1–2 GHz bandwidth amplifier enables a better sensitivity in the self-pumping frequency mixing mode, avoiding the 1/f noise. The dependence of the spectral density of noise on voltage was compared to the data for the Josephson emission linewidth obtained by the selective detector response method. Also discussed are measurements at 500 GHz of the NEP values carried out at different experimental conditions.
IEEE Transactions on Applied Superconductivity, Vol. 15, No. 2, June 2005, p.533-536
Papers in Russian
О возможности образования BaCeO3 при осаждении пленок YBa2Cu3O7-x
на поверхность оксида церия.
А.Д. Маштаков, И.М. Котелянский, В.А. Лузанов, П.Б. Можаев, Г.А. Овсянников,
И.Д. Бдикин
В работе представлены экспериментальные результаты исследования
кристаллографических параметров пленочных гетероструктур (1102)Al2O3/(001)CeO2/(001)YBa2Cu3O7-x,
полученных методом катодного распыления при высокой температуре T=600-800°C
подложки. Показано, что основное ограничение по тематуре осаждения пленки YBa2Cu3O7-x
на поверхность CeO2 вызвано химичеcким взаимодействием YBa2Cu3O7-x
с CeO2 с образованием поликристаллического слоя BaCeO3.
Письма в ЖТФ, 1997, том 23, № 19, стр. 8-13 (1997)
Особенности двойниковой структуры эпитаксиальных пленок YBa2Cu3O7-x.
И.К. Бдикин, А.Д. Маштаков, П.Б.Можаев, Г.А. Овсянников
Методами рентгеновской дифракции исследованы пленки YBa2Cu3O7-x
(YBCO) на NdGaO3 (110) и гетероструктуре (100) CeO2/(1102)Al2O3.
Для получения дифракционных спектров от различных кристаллографических
плоскостей применялись симметричная, несимметричная и аксиальная геометрии
рентгеновского сканирования q и q/2q.
Определены ориентационные и количественные характеристики двойникования пленок.
При близости кристаллографических параметров этих двух типов пленок (пленки c-ориентированы
с c=11.67 A) в структуре двойникования они имеют различия. В частности,
особенности структуры NdGaO3 приводят к возникновению угла, отличного
от 90° (90.20°), между возможными плоскостями двойникования (110) и (110)
в пленке YBCO и различному количеству двойниковых компонент в каждой системе
двойников. Из анализа уширения рефлексов, чувствительных к двойникованию, для
пленки YBCO на Al2O3 с буферным слоем CeO2
сделан вывод об отсутствии двойникования для 60% пленки.
Физика твердого тела, том 40, № 4, стр. 609-611 (1998)
Фазовая зависимость сверхпроводящего тока в YBCO джозефсоновских переходах
на бикристаллической подложке
Г.А. Овсянников, И.В. Борисенко, К.И. Константинян, А.Д. Маштаков, Е.А.
Степанцов
По экспериментальному измерению зависимостей амплитуд
гармонических и субгармонических ступенек Шапиро от внешнего монохроматического
воздействия изучена ток-фазовая зависимость ВТСП переходов на бикристаллической
подложке. Показано, что при симметричном задании транспортного тока через
переход с прозрачностью границы порядка D=10-4 и
зеркально-симметричной бикристаллической границы ток-фазовая зависимость близка
к синусоидальной, что отличается от предсказаний теории и, вероятно, вызвано
двойникованием ВТСП пленок электродов, образующих переход. Отклонение от
симметрии в задании транспортного тока через переход приводит к отклонению
ток-фазовой зависимости от синусоидальной, возрастающей с увеличением степени
асимметрии. Данное изменение ток-фазовой зависимости хорошо описывается моделью,
учитывающей возникновение связанных андреевских состояний в переходах
сверхпроводников с dx2-y2 типом сверхпроводящей
волновой функции.
Письма в ЖТФ, том 25, вып. 22, стр. 65-72 (1999)
Влияние параметров лазерного распыления на ориентацию буферного слоя оксида
церия на сапфире и свойства сверхпроводящей пленки YBa2Cu3Ox
П.Б. Можаев, Г.А. Овсянников, Й.Л. Сков
Исследовано влияние параметров лазерного распыления на
кристаллические свойства буферных слоев CeO2, выращенных на
сапфировой подложке ориентации (1102), и на свойства сверхпроводящих
тонких пленок YBa2Cu3Ox. Показано, что в
зависимости от условий напыления наблюдается рост ориентаций (100) и (111) CeO2.
Изменяя температуру нагревателя, давление в камере и плотность энергии лазерного
луча на мишени, удается получить одноориентированный буферный слой желаемой
ориентации.
Журнал технической физики, том 69, вып. 2, стр. 119-123 (1999)
Замещения в катионной подсистеме Nd/Ba в тонких пленках высокотемпературного
сверхпроводника NdBa2Cu3Oy.
П.Б. Можаев, Ф.В. Комиссинский, З.Г.Иванов, Г.А. Овсянников
Тонкие пленки высокотемпературного сверхпроводника Nd1+xBa2-xCu3Oy
(NBCO) с разным соотношением атомов неодима и бария были получены методом
совместного лазерного распыления мишеней с различным элементным составом. Пленки
с избытком неодима (x > 0) имели низкую плотность частиц на поверхности и
шероховатость, однако критическая температура пленок понижалась с ростом x.
Пленки с избыточным барием (x < 0) напротив, демонстрировали
независимость сверхпроводниковых свойств от состава осаждаемой пленки, а на
поверхности пленок наблюдалось значительное количество частиц. По-видимому,
замещение Nd на Ba в тонких пленках NBCO затруднено и избыточный Ba выделяется в
частицы (Ba,Cu)Oz. Структура и сверхпроводниковые свойства NBCO
демонстрируют сильную зависимость от условий насыщения пленок кислородом.
Физика твердого тела, том 42, вып. 96, стр. 1547-1552 (2000)
Температурная зависимость электронного транспорта в гетеропереходах нормальный металл-ВТСП.
Ф. В. Комиссинский, Г. А. Овсянников, З. Г. Иванов
ФТТ т. 43, стр. 769 (2001)
Рост и доменная структура пленок YBa2Cu3Ox на подложках галлата неодима с отклонением нормали поверхности от [110] NdGaO3
И.К. Бдикин, П.Б. Можаев, Г.А. Овсянников, Ф.В. Комиссинский, И.М. Котелянский, Е.И. Ракша
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Физика низких температур, 2004, т.30, N7/8, с.795-809
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И.В. Борисенко, К.И. Константинян, Ю. Кислинский, Г. А. Овсянников
ЖЭТФ 2004, т.99, N6, с.1402-1412
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