Magnetoresistance above and below Tc in c-axis-oriented YBa2Cu3O7−δ

✍ Scribed by Bai-ru Zhao; Kazuyuki Shiraki; Yuuji Horie; Shoichi Mase; Yin-zi Zhang; Yu-ying Zhao; Lan-fong Chen; Po Xu; Lin Li

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 642 KB
• Volume: 167
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(90)90482-t

✦ Synopsis

Electrical resistivity p( T, H) of c-axis-oriented

YBazCuj0,_8 thin films was measured under high magnetic fields up to H= 11 T. Following a proposal about the mechanism of magnetoresistance below T, in high-T, oxide superconductors made in previous papers, we have shown that the peculiar anisotropic curves of magnetoresistance can be well reproduced in terms of an empirical formula. The proposal is based on an inference that the coherence length is very short, so that the flux lattice cannot be kept in a regular lattice state in higher temperature and magnetic field regions beyond the flux creep region. Some experimental evidence for this inference is stated. Based on this inference, the coherence length derived from the fluctuation conductivity above I", is

shown to be nearly equal to that from -dHcz( T)/dTat T< T,, which was obtained from a large x0, criterion in p( T, H) versus T curves.