Configurational anisotropy in nanomagnets

Abstract

A novel magneto-optical method has been used to probe the internal magnetic energy surface in 150×150×15nm3 square Ni80Fe14Mo5 (“supermalloy”) nanomagnets which were fabricated by electron beam lithography. A strong fourfold symmetric anisotropy field of strength 365±20Oe is found, which confirms a recent prediction of the appearance of a configurational anisotropy due to the small deviations of the magnetization from the uniform state. © 1998 The American Physical Society.