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Effect of Magnetic Impurities in Crystalline and Amorphous States of Superconductors

Mi-Ae Park·Kerim Savran·Yong-Jihn Kim
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Abstract

It has been observed that the effect of magnetic impurities in a superconductor is drastically different depending on whether the host superconductor is in a crystalline or an amorphous state. Based on the recent theory of Kim and Overhauser, it is shown that as the system is getting disordered, the initial slope of the $T_{c}$ depression is decreasing by a factor $\sqrt{\ell/ξ_{0}}$, when the mean free path $\ell$ becomes smaller than the BCS coherence length $ξ_{0}$, which is in agreement with experimental findings. In addition, for a superconductor in a pure crystalline state the superconducting transition temperature $T_{c}$ drops sharply from about 50% of $T_{c0}$ (for a pure system) to zero near the critical impurity concentration. This {\sl pure limit behavior} was indeed found by Roden and Zimmermeyer in crystalline Cd.

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Mi-Ae Park, Kerim Savran, Yong-Jihn Kim. 2000-12-08. Effect of Magnetic Impurities in Crystalline and Amorphous States of Superconductors. https://arxiv.org/abs/cond-mat/0012136

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