engleski

Effect of Zn substitution on the normal state magnetoresistivity of epitaxial Y0.95Ca0.05Ba2(Cu{; ; ; 1-x}; ; ; Znx)3Oy and Y0.9Ca0.1Ba2Cu3Oy films

We report measurements of the in-plane resistivity, magneto-resistivity (MR) and Hall effect of slightly under- and nearly optimally-doped Y0.95Ca0.05Ba2(Cu{; ; ; 1-x}; ; ; Znx)3Oy (with x = 0, 0.02, 0.04) and overdoped Y0.9Ca0.1Ba2Cu3Oy films. We found that the introduction of Zn as a dopant strongly suppresses the orbital MR in the normal state. Surprisingly it obeys a T^{; ; ; -4}; ; ; law at lower temperatures where the resistivity and cotangent of the Hall angle are relatively constant and no longer obey the usual T^{; ; ; 1}; ; ; and T^{; ; ; 2}; ; ; laws, respectively. In other words, in these samples the increase in residual scattering rate produced by Zn has a stronger effect on cotangent of the Hall angle than on the MR at low T. It seems that this new result requires some modification of well-known theories involving two distinct relaxation processes for transport and Hall currents.

Superconductivity; Fluctuations; Transport properties; YBCO; Effects of crystal defects; Doping and substitution

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