Effect of Hafnium Impurities on the Magnetoresistance of $$\hbox {YBa}_{2}\hbox {Cu}_{3}\hbox {O}_{7-\delta }$$ YBa 2 Cu 3 O 7 - δ

Abstract

In the present study, we investigate the influence of the hafnium (Hf) impurities on the magnetoresistance of YBa 2 Cu 3 O 7−δ ceramic samples in the temperature interval of the transition to the superconducting state in constant magnetic field up to 12 T. The cause of the appearance of low-temperature "tails" (paracoherent transitions) on the resistive transitions, corresponding to different phase regimes of the vortex matter state is discussed. At temperatures higher than the critical temperature (T > T c ), the temperature dependence of the excess paraconductivity can be described within the Aslamazov-Larkin theoretical model of the fluctuation conductivity for layered superconductors.

Electro- and Heat Transfer in $$\mathbf{Cd}_{\mathbf{0.22}}\mathbf{\hbox {Hg}}_{\mathbf{0.78}}{} \mathbf{Te}$$ Cd 0.22 Hg

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