Synthesis, transformation and superconductivity of dual phase In–Sn alloy nanoparticles embedded in an Al matrix

Abstract

We report the synthesis of nanoembedded biphasic alloy particles of In–Sn near eutectic alloy compositions embedded in an aluminium matrix by rapid solidification processing. Detailed transmission electron microscopy indicates that the two phases present at room temperature in as-synthesized samples are β and γ phases with tetragonal and hexagonal crystal structures, respectively. These co-exist with a small amount of single phase In or Sn particles with sizes less than 10 nm. Low temperature magnetization measurements indicate a superconducting transition temperature of 5 K, suggesting complete decomposition of the β-phase at small sizes and at low temperature. The small particles show type II behavior with a critical field Hc₁≈44 G and two values for Hc₂ of 250 and 1000 G, respectively. These values are considerably lower than those observed in bulk In–Sn alloys.

Acknowledgement

The authors wish to acknowledge the Department of Science and Technology, Government of India, for financial support.