Properties of Tl2Ba2CaCu2O8 step and bicrystal junctions and dc-SQUIDs on LaAlO3 substrates

Y. F. Chen; Z. G. Ivanov; E. A. Stepantsov; A. Y. Tzalenchuk; S. Zarembinski; A. L. Vasiliev; E. Olsson; H. R. Yi; T. Claeson; L. G. Johansson

Properties of Tl2Ba2CaCu2O8 step and bicrystal junctions and dc-SQUIDs on LaAlO3 substrates

Y. F. Chen, Z. G. Ivanov, E. A. Stepantsov, A. Y. Tzalenchuk, S. Zarembinski, A. L. Vasiliev, E. Olsson, H. R. Yi, T. Claeson, L. G. Johansson

Department of Physics

Research output: Chapter in Book/Report/Conference proceeding › Other contribution

Abstract

Step and bicrystal Josephson junctions and de SQUIDs in Tl-2212 epitaxial films have been fabricated and studied. The junctions formed on steps with an angle of 68 degrees have hysteretic multi-branch I-V curves and J(c) approximate to 10(3) A/cm(2) at 4K. TEM images show that Tl-2212 forms an a-axis bar-like grain on the step which is surrounded by c-axis oriented film. However, the supercurrent transport at the step is most likely determined by Josephson tunneling between the Cu-O planes in the c-direction of this grain rather than through the 90 degrees a-axis tilted grain boundaries formed at the step edges. The transport measurements on 32 degrees bicrystal junctions showed that such a grain boundary behaves as a Josephson junction with a J(c) of 6 . 10(3)-2 . 10(4) A/cm(2) while the intragrain J(c) was approximate to 2 . 10(6) A/cm(2), both measured at 77K. The critical temperature of the junctions is in the range 89-108K. The critical current is found to be proportional to (1-T/T-c)(2) at temperatures close to T-c, whereas at low temperatures I-c proportional to 1-T/T-c. The flux noise, S-Phi, of de SQUIDs is measured up to 95K in the locked mode without bias reversing. At 77K the white noise level is 50 mu Phi(0)/root Hz. The crossover frequency to 1/f noise is low, about 5Hz, and the flux noise level at 1 Hz is 440 mu Phi(0)/root Hz.

Original language	English
Title of host publication	Applied Superconductivity 1995, Vols. 1 and 2: Vol 1: Plenary Talks and High Current Applications; Vol 2: Small Scale Applications
Pages	1335-1338
Number of pages	4
Volume	148
Publication status	Published - 1995

Publication series

Name	Institute of Physics Conference Series

Cite this

Chen, Y. F., Ivanov, Z. G., Stepantsov, E. A., Tzalenchuk, A. Y., Zarembinski, S., Vasiliev, A. L., Olsson, E., Yi, H. R., Claeson, T., & Johansson, L. G. (1995). Properties of Tl2Ba2CaCu2O8 step and bicrystal junctions and dc-SQUIDs on LaAlO3 substrates. In Applied Superconductivity 1995, Vols. 1 and 2: Vol 1: Plenary Talks and High Current Applications; Vol 2: Small Scale Applications (Vol. 148, pp. 1335-1338). (Institute of Physics Conference Series).

@inbook{0871783b97f6497d9ace4756608e1aca,

title = "Properties of Tl2Ba2CaCu2O8 step and bicrystal junctions and dc-SQUIDs on LaAlO3 substrates",

abstract = "Step and bicrystal Josephson junctions and de SQUIDs in Tl-2212 epitaxial films have been fabricated and studied. The junctions formed on steps with an angle of 68 degrees have hysteretic multi-branch I-V curves and J(c) approximate to 10(3) A/cm(2) at 4K. TEM images show that Tl-2212 forms an a-axis bar-like grain on the step which is surrounded by c-axis oriented film. However, the supercurrent transport at the step is most likely determined by Josephson tunneling between the Cu-O planes in the c-direction of this grain rather than through the 90 degrees a-axis tilted grain boundaries formed at the step edges. The transport measurements on 32 degrees bicrystal junctions showed that such a grain boundary behaves as a Josephson junction with a J(c) of 6 . 10(3)-2 . 10(4) A/cm(2) while the intragrain J(c) was approximate to 2 . 10(6) A/cm(2), both measured at 77K. The critical temperature of the junctions is in the range 89-108K. The critical current is found to be proportional to (1-T/T-c)(2) at temperatures close to T-c, whereas at low temperatures I-c proportional to 1-T/T-c. The flux noise, S-Phi, of de SQUIDs is measured up to 95K in the locked mode without bias reversing. At 77K the white noise level is 50 mu Phi(0)/root Hz. The crossover frequency to 1/f noise is low, about 5Hz, and the flux noise level at 1 Hz is 440 mu Phi(0)/root Hz.",

author = "Chen, {Y. F.} and Ivanov, {Z. G.} and Stepantsov, {E. A.} and Tzalenchuk, {A. Y.} and S. Zarembinski and Vasiliev, {A. L.} and E. Olsson and Yi, {H. R.} and T. Claeson and Johansson, {L. G.}",

year = "1995",

language = "English",

volume = "148",

series = "Institute of Physics Conference Series",

pages = "1335--1338",

booktitle = "Applied Superconductivity 1995, Vols. 1 and 2: Vol 1: Plenary Talks and High Current Applications; Vol 2: Small Scale Applications",

}

Chen, YF, Ivanov, ZG, Stepantsov, EA, Tzalenchuk, AY, Zarembinski, S, Vasiliev, AL, Olsson, E, Yi, HR, Claeson, T & Johansson, LG 1995, Properties of Tl2Ba2CaCu2O8 step and bicrystal junctions and dc-SQUIDs on LaAlO3 substrates. in Applied Superconductivity 1995, Vols. 1 and 2: Vol 1: Plenary Talks and High Current Applications; Vol 2: Small Scale Applications. vol. 148, Institute of Physics Conference Series, pp. 1335-1338.

Properties of Tl2Ba2CaCu2O8 step and bicrystal junctions and dc-SQUIDs on LaAlO3 substrates. / Chen, Y. F.; Ivanov, Z. G.; Stepantsov, E. A. et al.
Applied Superconductivity 1995, Vols. 1 and 2: Vol 1: Plenary Talks and High Current Applications; Vol 2: Small Scale Applications. Vol. 148 1995. p. 1335-1338 (Institute of Physics Conference Series).

Research output: Chapter in Book/Report/Conference proceeding › Other contribution

TY - CHAP

T1 - Properties of Tl2Ba2CaCu2O8 step and bicrystal junctions and dc-SQUIDs on LaAlO3 substrates

AU - Chen, Y. F.

AU - Ivanov, Z. G.

AU - Stepantsov, E. A.

AU - Tzalenchuk, A. Y.

AU - Zarembinski, S.

AU - Vasiliev, A. L.

AU - Olsson, E.

AU - Yi, H. R.

AU - Claeson, T.

AU - Johansson, L. G.

PY - 1995

Y1 - 1995

N2 - Step and bicrystal Josephson junctions and de SQUIDs in Tl-2212 epitaxial films have been fabricated and studied. The junctions formed on steps with an angle of 68 degrees have hysteretic multi-branch I-V curves and J(c) approximate to 10(3) A/cm(2) at 4K. TEM images show that Tl-2212 forms an a-axis bar-like grain on the step which is surrounded by c-axis oriented film. However, the supercurrent transport at the step is most likely determined by Josephson tunneling between the Cu-O planes in the c-direction of this grain rather than through the 90 degrees a-axis tilted grain boundaries formed at the step edges. The transport measurements on 32 degrees bicrystal junctions showed that such a grain boundary behaves as a Josephson junction with a J(c) of 6 . 10(3)-2 . 10(4) A/cm(2) while the intragrain J(c) was approximate to 2 . 10(6) A/cm(2), both measured at 77K. The critical temperature of the junctions is in the range 89-108K. The critical current is found to be proportional to (1-T/T-c)(2) at temperatures close to T-c, whereas at low temperatures I-c proportional to 1-T/T-c. The flux noise, S-Phi, of de SQUIDs is measured up to 95K in the locked mode without bias reversing. At 77K the white noise level is 50 mu Phi(0)/root Hz. The crossover frequency to 1/f noise is low, about 5Hz, and the flux noise level at 1 Hz is 440 mu Phi(0)/root Hz.

AB - Step and bicrystal Josephson junctions and de SQUIDs in Tl-2212 epitaxial films have been fabricated and studied. The junctions formed on steps with an angle of 68 degrees have hysteretic multi-branch I-V curves and J(c) approximate to 10(3) A/cm(2) at 4K. TEM images show that Tl-2212 forms an a-axis bar-like grain on the step which is surrounded by c-axis oriented film. However, the supercurrent transport at the step is most likely determined by Josephson tunneling between the Cu-O planes in the c-direction of this grain rather than through the 90 degrees a-axis tilted grain boundaries formed at the step edges. The transport measurements on 32 degrees bicrystal junctions showed that such a grain boundary behaves as a Josephson junction with a J(c) of 6 . 10(3)-2 . 10(4) A/cm(2) while the intragrain J(c) was approximate to 2 . 10(6) A/cm(2), both measured at 77K. The critical temperature of the junctions is in the range 89-108K. The critical current is found to be proportional to (1-T/T-c)(2) at temperatures close to T-c, whereas at low temperatures I-c proportional to 1-T/T-c. The flux noise, S-Phi, of de SQUIDs is measured up to 95K in the locked mode without bias reversing. At 77K the white noise level is 50 mu Phi(0)/root Hz. The crossover frequency to 1/f noise is low, about 5Hz, and the flux noise level at 1 Hz is 440 mu Phi(0)/root Hz.

M3 - Other contribution

VL - 148

T3 - Institute of Physics Conference Series

SP - 1335

EP - 1338

BT - Applied Superconductivity 1995, Vols. 1 and 2: Vol 1: Plenary Talks and High Current Applications; Vol 2: Small Scale Applications

ER -

Chen YF, Ivanov ZG, Stepantsov EA, Tzalenchuk AY, Zarembinski S, Vasiliev AL et al. Properties of Tl2Ba2CaCu2O8 step and bicrystal junctions and dc-SQUIDs on LaAlO3 substrates. In Applied Superconductivity 1995, Vols. 1 and 2: Vol 1: Plenary Talks and High Current Applications; Vol 2: Small Scale Applications. Vol. 148. 1995. p. 1335-1338. (Institute of Physics Conference Series).