Magnetoresistance in HTSC far above T<sub>c</sub>: fluctuations versus normal-state contributions

Author(s): W. Lang, G. Heine, W. Liebich, X. L. Wang, X. Z. Wang
Abstract: We discuss the temperature dependence of the anisotropic magnetoresistance in high temperature superconductors with a focus on the magnetoresistance at temperatures significantly above T/sub c/. Recent results on YBa/sub 2/Cu/sub 3/O/sub 7- delta / thin films and single crystals are analyzed and measurements of the in-plane and out-of-plane magnetoresistance in optimally doped Bi/sub 2/Sr/sub 2/CaCu/sub 2/O/sub 8+x/ single crystals are reported. The in-plane magnetoresistance of both YBa/sub 2/Cu/sub 3/O/sub 7- delta / and Bi/sub 2/Sr/sub 2/CaCu/sub 2/O/sub 8+x/ is positive for magnetic fields oriented perpendicular and parallel to the current. The out-of-plane magnetoresistance of Bi/sub 2/Sr/sub 2/CaCu/sub 2/O/sub 8+x/ is negative from 94 to 180 K. The results are discussed considering the magnetic-field suppression of superconducting fluctuations including the Aslamazov-Larkin and Maki-Thompson terms, the normal-state magnetoresistance of quasiparticles, and the reduction of the quasiparticle density of states due to condensation into superconducting fluctuations. A crossover from fluctuation-induced in-plane magnetoresistance close to T/sub c/ to the quasiparticle effect was found around 1.25 T/sub c/. The out-of-plane magnetoresistance is dominated by the density-of-states contribution. All results indicate that superconducting fluctuations persist up to at least 2T/sub c/.
Organisation(s): Electronic Properties of Materials
Pages: 81-90
No. of pages: 10
DOI: https://doi.org/10.1007/978-94-011-5536-6_6
Publication date: 1997
Austrian Fields of Science 2012: 103018 Materials physics
Keywords
Portal url: https://ucris.univie.ac.at/portal/en/publications/magnetoresistance-in-htsc-far-above-tc-fluctuations-versus-normalstate-contributions(582ba2bc-8e48-4519-936c-52c17a9c855d).html