Non-equilibrium materials design: a case study of nanostructured soft magnets for cryogenic applications

Nanocrystalline soft magnetic materials are the latest and most promising of the soft magnetic materials that were developed at the end of the 20th century. They have since been studied extensively, and various alloy compositions have been developed and optimized for ambient and extreme (cryogenic and elevated temperature) applications. Their advantage lies in the unique combination of fine microstructure, crystal structure and composition, which can be achieved by rapid solidification and subsequent controlled annealing. In this article, we discuss the requirements and the challenges of the alloy designing these alloys and how it affects the crystal structure, microstructure and eventually the magnetic performance of new alloys designed for use at temperatures below 150 K in applications as varied as cryo-power electronics and magnetic shielding. The results from our latest studied alloy series are mentioned as an example.