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Title:Hall effect in the superconducting and normal states in detwinned and twinned single crystals of zinc-doped YBa2Cu3O7-d
Author(s):Schegolev, Anton Igorevich
Doctoral Committee Chair(s):Ginsberg, D.M.
Department / Program:Physics
Subject(s):Hall effect
single crystal
zinc doping
twinned, detwinned
Abstract:We have investigated the influence of zinc doping on the Hall effect in detwinned and twinned single crystals of YBa2Cu307..o. We observed the sign reversal of the Hall effect for crystals with superconducting transition temperature (Tc) as low as 58.51 K. Below the transition temperature, the Hall conductivity followed the CdH+C2H law. According to the theory of the Hall effect in the mixed state [1], the first term comes from the vortex motion's contribution, and the other term comes from the quasiparticles in the vortex cores. We found that absolute value of the coefficient C1 increased faster than (1-T/Tc) with decreasing temperature. The C2 coefficient was found to increase rapidly as T fell below Tc for crystals with Tc higher than 70K, supposedly because of the sharp increase in the quasiparticle mean free path. We also found that the Hall effect is different in twinned and detwinned crystals; we found that the Hall coefficient in the normal state increased almost 20% after detwinning. The C1 coefficient was found to be almost unaffected by twin boundaries while the C2 coefficient increased a factor of two after detwinning. Such a behavior of C 1 suggests that the twin boundaries do not affect vortex motion once the field exceeds the depinning one. The substantial increase of C2 and the Hall coefficient in the normal state by the detwinning points out that the disorder in the basal (or chain) plane is important for charge movement in the Cu02 plane, and the disorder affects the process of charge transfer from chains to planes. The depinning field was found to decrease during the removal of twin boundaries. This fact supports an idea that twin boundaries serve to pin vortices in YBa2Cu307.o. The solubility limit of zinc in YBa2Cu30 7.o single crystals was found to be slightly less then 4%. This material is based upon work supported by National Science Foundation under Grant DMR 89-20538. [1] A.T. Dorsey, Phys. Rev. B 46, 8376 (1992)~ N.B. Kopnin, B.I. Ivlev, and V.A. Khalatsky, J. Low Temp. Phys. 90, 1 (1993)~ R.J. Troy and A.T. Dorsey, Phys. Rev. B 47, 2715 (1993).~ M.Feigel'man, V.Geshkenbein, A.Larkin, V.Vinokur, JETP Lett. 62, 834 (1995). iv
Issue Date:1996
Genre:Dissertation / Thesis
Rights Information:1996 Anton Igorevich Schegolev
Date Available in IDEALS:2011-04-19
Identifier in Online Catalog:4016613

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