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

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

Published

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

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

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.

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).

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).

@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",

}

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 -