摘要
Temperature-dependent resistivity, thermoelectric power, and magnetoresistance (MR) are investigated in Y Ba2 Cu3 O7 La0.7 Sr0.3 Mn O3 (YBCO/LSMO) bilayers with the thickness of YBCO fixed at 150 nm and that of LSMO varying from t=0 to 50 nm. It is found that the onset temperature Tc of the superconducting transition retains at a constant value of 74 K for t<50 nm, but reduces to 20 K at t=50 nm. In conjunction with the existence of a critical thickness of 50 nm for delocalizing charge carriers in the LSMO layer, we attribute the Tc suppression to the diffusion of spin-polarized carriers from the metallic LSMO to the YBCO layer. Furthermore, we observe a sign reversal of MR with temperature in the YBCO(150 nm)/LSMO(50 nm) bilayer, indicating a competition between a positive MR of YBCO and a negative MR of LSMO.
原文 | ???core.languages.en_GB??? |
---|---|
文章編號 | 023910 |
期刊 | Journal of Applied Physics |
卷 | 98 |
發行號 | 2 |
DOIs | |
出版狀態 | 已出版 - 15 7月 2005 |