ZIB

1

Electronic Resource

Growth and properties of a multilayer system based on Y1Ba2Cu3Ox and amorphous Y-ZrO2 (1992)

Boikov, Yu. ; Ivanov, Z. G. ; Olsson, E. ; [et al.]

[S.l.] : American Institute of Physics (AIP)

Journal of Applied Physics 72 (1992), S. 199-202

add to mindlist on the mindlist

Details

ISSN: 1089-7550

Source: AIP Digital Archive

Topics: Physics

Notes: The growth of c-axis oriented Y1Ba2Cu3Ox thin films on an amorphous buffer layer of Y-ZrO2, deposited on sapphire substrates, was investigated. Both films were grown by a pulsed laser deposition technique. A strong correlation was observed between the properties of Y1Ba2Cu3Ox and the thickness of the buffer layer. A Tc of 89 K was obtained for an optimal buffer layer thickness of 9 nm. A model that adequately describes the film growth process was developed. A multilayer system of Y1Ba2Cu3Ox and amorphous Y-ZrO2 was grown and a Tc of 87 K for the upper c-axis oriented layer was measured.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.352157

Permalink

Library	Location	Call Number	Volume/Issue/Year	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

2

Electronic Resource

YBa2Cu3O7/NdGaO3/YBa2Cu3O7 trilayers by modified off-axis sputtering (1993)

Wang, S. Z. ; Olsson, E. ; Alarco, J. A. ; [et al.]

[S.l.] : American Institute of Physics (AIP)

Journal of Applied Physics 73 (1993), S. 7543-7548

add to mindlist on the mindlist

Details

ISSN: 1089-7550

Source: AIP Digital Archive

Topics: Physics

Notes: High-quality epitaxial YBa2Cu3O7−δ (YBCO) thin films were achieved by a modified off-axis sputtering technique with high deposition rates (3.3 nm/min). The film quality and the deposition rate depended crucially on the target-to-substrate separation. Epitaxial YBCO/NdGaO3(NGO)/YBCO trilayers were successfully grown onto SrTiO3, Y-ZrO2, and LaAlO3 substrates by dc and rf sputtering. The epitaxial relations were found to be [001]YBCO//[001]NGO, [100]YBCO, or [010]YBCO//[110]NGO and [001]YBCO//[110]NGO, [100]YBCO, or [010]YBCO//[001]NGO, where the latter orientation relationship was dominating. Subsequent top YBCO layers grew c axis oriented independently of the two epitaxial orientations of the NGO. The orientation relationships between YBCO and NGO were the same. Auger electron depth profiles and transmission electron microscopy indicated that the interdiffusion at the interface between the YBCO and NGO layers was not strong even at 740 °C. The superconducting transition temperatures of the top and bottom YBCO layers were about the same as that of YBCO single layers, i.e., 87–90 K. Scanning electron microscopy of the surface morphologies of the YBCO and the NGO showed that a smaller substrate-target distance resulted in smoother films.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.354002

Permalink

Library	Location	Call Number	Volume/Issue/Year	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

3

Electronic Resource

Epitaxial YBa2Cu3O7−δ /BaxSr1−xTiO3 heterostructures on silicon-on-sapphire for tunable microwave components (1995)

Boikov, Yu. A. ; Ivanov, Z. G. ; Kiselev, A. N. ; [et al.]

[S.l.] : American Institute of Physics (AIP)

Journal of Applied Physics 78 (1995), S. 4591-4595

add to mindlist on the mindlist

Details

ISSN: 1089-7550

Source: AIP Digital Archive

Topics: Physics

Notes: Epitaxial trilayer heterostructures of YBa2Cu3O7−δ/BaxSr1−xTiO3/YBa2Cu3O7−δ were grown on silicon-on-sapphire buffered by a double layer of CeO2/Y–ZrO2. Such structures may be considered for tunable microwave filters. The top and bottom YBa2Cu3O7−δ films were well c-axis oriented, free from microcracks and had superconducting transitions Tc's in the range 86–90 K. A thin antidiffusion layer of SrTiO3 (d≈70 A(ring)) between YBa2Cu3O7−δ and BaxSr1−xTiO3 (x=0.25–0.9) promoted better crystallinity and higher Tc of the top superconducting film. An Ag/BaxSr1−xTiO3/YBa2Cu3O7−δ capacitor structure was used to determine the dielectric permittivity and the high frequency loss tan δ of the BaxSr1−xTiO3 layer. Maximum values of the permittivity of the BaxSr1−xTiO3 layers were observed around the Curie temperatures of corresponding bulk monocrystals. The dielectric permittivity of the BaxSr1−xTiO3 (x=0.25–0.75) layers depended strongly (≈20%) on an applied voltage (±2.5 V) at temperatures around 77 K. The tan δ was much higher in films than in bulk crystals. © 1995 American Institute of Physics.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.359804

Permalink

Library	Location	Call Number	Volume/Issue/Year	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

4

Electronic Resource

Microwave testing of high-Tc based direct current to a single flux quantum converter (1994)

Kaplunenko, V. K. ; Fischer, G. M. ; Ivanov, Z. G. ; [et al.]

[S.l.] : American Institute of Physics (AIP)

Journal of Applied Physics 76 (1994), S. 5996-6000

add to mindlist on the mindlist

Details

ISSN: 1089-7550

Source: AIP Digital Archive

Topics: Physics

Notes: Design, simulation, and experimental investigations of a direct current to a single flux quantum converter loaded with a Josephson transmission line and driven by an external 70 GHz microwave oscillator are reported. The test circuit includes nine YBaCuO Josephson junctions aligned on the grain boundary of a 0°–32° asymmetric Y-ZrO2 bicrystal substrate. The performance of such converters is important for the development of the fast Josephson samplers required for testing of high-Tc rapid single flux quantum circuits in high-speed digital superconducting electronics.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.358383

Permalink

Library	Location	Call Number	Volume/Issue/Year	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

5

Electronic Resource

Transport properties of Tl2Ba2CaCu2O8 weak links on LaAlO3 bicrystal substrates (1996)

Chen, Y. F. ; Ivanov, Z. G. ; Stepantsov, E. A. ; [et al.]

[S.l.] : American Institute of Physics (AIP)

Journal of Applied Physics 79 (1996), S. 9221-9223

add to mindlist on the mindlist

Details

ISSN: 1089-7550

Source: AIP Digital Archive

Topics: Physics

Notes: Josephson junctions and dc superconducting quantum interference devices (SQUIDs) have been fabricated in ex situ epitaxial Tl2Ba2CaCu2O8 films on bicrystal LaAlO3 substrates with symmetric 32° [001] tilt grain boundaries. The critical temperature Tc, of the junctions was in the range 105–107 K and the critical current densities at 77 K varied between 3×102 and 3×104 A/cm2, two or three orders of magnitude less than those of the film. The I–V curves are described by a resistively shunted junction model. Close to Tc, the temperature dependence of the critical current was described by (1−T/Tc)2. The flux noise spectra SΦ(f) of dc SQUIDs were measured in the locked-loop regime with constant current bias at temperatures up to 94 K. The white noise level was 50μΦ0/(square root of)Hz at 77 K. The crossover frequency to 1/f noise was low, about 5 Hz, and the flux noise level at 1 Hz was 440μΦ0/(square root of)Hz. © 1996 American Institute of Physics.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.362595

Permalink

Library	Location	Call Number	Volume/Issue/Year	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

6

Electronic Resource

Biepitaxial Josephson junctions with high critical current density based on YBa2Cu3O7−δ films on silicon on sapphire (1995)

Boikov, Yu. A. ; Ivanov, Z. G. ; Vasiliev, A. L. ; [et al.]

[S.l.] : American Institute of Physics (AIP)

Journal of Applied Physics 77 (1995), S. 1654-1657

add to mindlist on the mindlist

Details

ISSN: 1089-7550

Source: AIP Digital Archive

Topics: Physics

Notes: High-current-density Josephson junctions have been produced in high-temperature superconducting YBa2Cu3O7−δ films deposited on silicon on sapphire and using biepitaxial grain boundaries. The technique is estimated to be useful in integrating superconducting and semiconducting components. A multilayer system of epitaxially grown films was used to form the junctions. A double buffer layer CeO2/ZrO2(9.5% Y2O3) prevented interactions between YBa2Cu3O7−δ and Si during the high-temperature deposition and promoted formation microcrack-free films with a critical current density of 2×106 A/cm2 at 77 K. A MgO seed layer, with (001)MgO(parallel)(001)CeO2 orientation, was used to induce a 45° crystallographic grain boundary in YBa2Cu3O7−δ at its edge. An additional epitaxial buffer double layer of YBa2Cu3O7−δ and SrTiO3 on top of the seed layer promoted the formation of a grain boundary of better crystallinity and stoichiometry. It improved the critical current of the junction about tenfold and resulted in characteristic IcRn products of 150 μV at 77 K in microbridges crossing the grain boundary. Microwave-induced steps were detected at 77 K up to voltages corresponding to the characteristic IcRn value. Peak-to-peak responses to superconducting quantum interference devices reached values of 7 μV at 77 K. © 1995 American Institute of Physics.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.358922

Permalink

Library	Location	Call Number	Volume/Issue/Year	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

7

Electronic Resource

Bicrystal junctions and superconducting quantum interference devices in YBa2Cu3O7 thin films (1994)

Nilsson, P. A(ring). ; Ivanov, Z. G. ; Olsson, H. K. ; [et al.]

[S.l.] : American Institute of Physics (AIP)

Journal of Applied Physics 75 (1994), S. 7972-7977

add to mindlist on the mindlist

Details

ISSN: 1089-7550

Source: AIP Digital Archive

Topics: Physics

Notes: Josephson junctions and superconducting quantum interference devices (SQUIDs) were made by depositing thin films of YBa2Cu3O7 on bicrystal substrates of Y-ZrO2 and SrTiO3. The critical current density of the junctions at 77 K could be adjusted from 100 to 106 A/cm2 by selecting bicrystals with misorientation angles θ from 45° to 0°. Current-voltage curves from junctions with θ(approximately-greater-than)22° followed the resistively shunted junction model with noise rounding close to the transition temperature. The response of the critical current to magnetic fields was Fraunhofer-like and the width (w) dependence was 1/w2 due to flux focusing effects. Shapiro steps under microwave radiation were observed. SQUIDs based on these junctions had energy resolutions at 77 K down to 8.6×10−30 J/Hz and a 10 Hz flux noise level down to 1.5×10−9 Φ20/Hz at 85 K. A SQUID of the Ketchen design with a flux focusing washer had a magnetic field sensitivity of 15 pT/(square root of)Hz at 77 K. The temperature dependence of the voltage modulation depth close to TC was examined and found to be in agreement with theory [K. Enpuku, Y. Shimomura, and T. Kisu, J. Appl. Phys. 73, 7929 (1993)].

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.356559

Permalink

Library	Location	Call Number	Volume/Issue/Year	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

8

Electronic Resource

YBa2Cu3O7−x films on yttria-stabilized ZrO2 substrates: Influence of the substrate morphology (1994)

Brorsson, G. ; Olsson, E. ; Ivanov, Z. G. ; [et al.]

[S.l.] : American Institute of Physics (AIP)

Journal of Applied Physics 75 (1994), S. 7958-7965

add to mindlist on the mindlist

Details

ISSN: 1089-7550

Source: AIP Digital Archive

Topics: Physics

Notes: c-axis-oriented YBa2Cu3O7−x (YBCO) thin films were laser deposited on (001) yttria-stabilized ZrO2 (YSZ) substrates with different surface morphologies. The in-plane orientation of the films on smooth substrates was sensitive to the deposition conditions, often resulting in mixed orientations. However, a strongly dominating [110]YBCO//[110]YSZ orientation was obtained at a deposition temperature of 770 °C. Films on substrates with surface steps, induced by depositing a homoepitaxial buffer layer or by thermally annealing the substrate, had a [110]YBCO//[100]YSZ orientation when deposited at the same temperature. It was concluded that the [110]YBCO//[100]YSZ orientation was promoted by a graphoepitaxial mechanism. Films prepared under identical conditions on smooth and stepped substrates grew with extended c axes on the former. It is proposed that the extension can be induced by disorder, invoked by a low oxygen pressure and a low density of adsorption sites. The disorder may be eliminated by either an increase of the oxygen pressure or an increase of the density of adsorption sites in the form of steps. The film microstructure influenced the microwave surface resistance, which was similar for films with one exclusive in-plane orientation and higher for films with mixed orientations. The films on the stepped surfaces had superior superconducting properties; inductive measurements gave a Tconset of 88 K, a ΔT(90%–10%)c of 0.2 K, and the transport jc was 1.5×106 A/cm2 at 83 K, for films on substrates with homoepitaxial buffer layers.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.356557

Permalink

Library	Location	Call Number	Volume/Issue/Year	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

9

Electronic Resource

Epitaxial growth and properties of YBa2Cu3Ox-Pb(Zr0.6Ti0.4)O3-YBa2Cu3Ox trilayer structure by laser ablation (1992)

Boikov, Yu. A. ; Esayan, S. K. ; Ivanov, Z. G. ; [et al.]

Woodbury, NY : American Institute of Physics (AIP)

Applied Physics Letters 61 (1992), S. 528-530

add to mindlist on the mindlist

Details

ISSN: 1077-3118

Source: AIP Digital Archive

Topics: Physics

Notes: We have grown YBa2Cu3Ox-Pb(Zr0.6Ti0.4)O3-YBa2Cu3Ox multilayer structure on SrTiO3 and Al2O3 substrates using laser ablation. The deposition conditions for the growth of trilayers and their properties are studied in this investigation. Scanning electron microscope images and x-ray diffraction analyses indicate that all the constituent films in the trilayer grow epitaxially on SrTiO3 and were highly oriented on Al2O3. Transport measurements on these multilayers show that top YBa2Cu3Ox films have good superconducting properties.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.107877

Permalink

Library	Location	Call Number	Volume/Issue/Year	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

10

Electronic Resource

Weak links and dc SQUIDS on artificial nonsymmetric grain boundaries in YBa2Cu3O7−δ (1991)

Ivanov, Z. G. ; Nilsson, P. A(ring). ; Winkler, D. ; [et al.]

Woodbury, NY : American Institute of Physics (AIP)

Applied Physics Letters 59 (1991), S. 3030-3032

add to mindlist on the mindlist

Details

ISSN: 1077-3118

Source: AIP Digital Archive

Topics: Physics

Notes: We have studied weak links and dc–SQUIDs made from pulsed laser deposited YBa2Cu3O7−δ thin films on Y–ZrO2 bicrystal substrates. The transport properties of the weak links were studied as a function of the misorientation angle (θ) between the two halves of the bicrystal and an exponential dependence of the weak link critical current density was observed for angles up to 40° at 77 K. Josephson effects with clear microwave and magnetic field responses were observed. An optimum dc–SQUID performance at 77 K was obtained for θ=32°. At this temperature, we achieved a periodic magnetic field response with a modulation depth of 12 μV.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.105783

Permalink

Library	Location	Call Number	Volume/Issue/Year	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext