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arXiv · 1512.01365

Superconductivity in im-miscible Cu-Nb phase separated nano-composite thin films

Pradnya Parab·Vivas Bagwe·Bhagyashree Chalke·H. Muthurajan·Pratap Raychaudhuri·Sangita Bose
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Abstract

Superconductivity in granular films is controlled by the grain size and the inter-grain coupling. In a two-component granular system formed by a random mixture of a normal metal (N) and a superconductor (S), the superconducting nano-grains may become coupled through S-N weak links, thereby affecting the superconducting properties of the network. We report on the study of superconductivity in immiscible Nb-Cu nanocomposite films with varying compositions. The microstructure of the films revealed the presence of phase separated, closely spaced, nano-grains of Nb and Cu whose sizes changed marginally with composition. The superconducting transition temperature (Tc0) of the films decreased with increasing concentration of Cu with a concomitant decrease in the upper critical field (Hc2) and the critical current (Ic). Our results indicate the presence of superconducting phase fluctuations in all films with varying Nb:Cu content which not only affected the temperature for the formation of a true phase coherent superconducting condensate in the films but also other superconducting properties.

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Pradnya Parab, Vivas Bagwe, Bhagyashree Chalke, H. Muthurajan, Pratap Raychaudhuri, Sangita Bose. 2015-12-04. Superconductivity in im-miscible Cu-Nb phase separated nano-composite thin films. https://doi.org/10.1088/1361-6668%2Faa63c0

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