Magnetization of underdoped YBa2Cu3Oy above the irreversibility field

Yu, Jing Fei and Ramshaw, B. J. and Kokanović, Ivan and Modic, K. A. and Harrison, N. and Day, James and Liang, Ruixing and Hardy, W. N. and Bonn, D. A. and McCollam, A. and Julian, S. R. and Cooper, J. R. (2015) Magnetization of underdoped YBa2Cu3Oy above the irreversibility field. Physical Review B, 92 (18). 180509(R)-5. ISSN 1098-0121

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Abstract

Torque magnetization measurements on YBa2Cu3Oy (YBCO) at doping y = 6.67 (p = 0.12), in dc fields (B) up to 33 T and temperatures down to 4.5 K, show that weak diamagnetism persists above the extrapolated irreversibility field Hirr(T = 0) ≈ 24 T. The differential susceptibility dM/dB, however, is more rapidly suppressed for B 16 T than expected from the properties of the low field superconducting state, and saturates at a low value for fields B 24 T. In addition, torque measurements on a p = 0.11 YBCO crystal in pulsed field up to 65 T and temperatures down to 8 K show similar behavior, with no additional features at higher fields. We offer two candidate scenarios to explain these observations: (a) superconductivity survives but is heavily suppressed at high field by competition with charge-density-wave (CDW) order; (b) static superconductivity disappears near 24 T and is followed by a region of fluctuating superconductivity, which causes dM/dB to saturate at high field. The diamagnetic signal observed above 50 T for the p = 0.11 crystal at 40 K and below may be caused by changes in the normal state susceptibility rather than bulk or fluctuating superconductivity. There will be orbital (Landau) diamagnetism from electron pockets and possibly a reduction in spin susceptibility caused by the stronger three-dimensional ordered CDW.

Item Type: Article
Date: 23 November 2015
Subjects: NATURAL SCIENCES > Physics
NATURAL SCIENCES > Physics > Condensed Matter Physics
Additional Information: Copyright (2015) by the American Physical Society. Received 18 September 2015; revised manuscript received 1 November 2015; published 23 November 2015.
Divisions: Faculty of Science > Department of Physics
Publisher: American Physical Society
Depositing User: Gordana Stubičan Ladešić
Date Deposited: 03 Feb 2016 13:00
Last Modified: 03 Feb 2016 13:00
URI: http://digre.pmf.unizg.hr/id/eprint/4494

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