Room-temperature magnetic skyrmion in epitaxial thin films of Fe_(2-x)Pd_xMo_3N with the filled β-Mn-type chiral structure

摘要

We report experimental observations of chiral magnetic skyrmion phases in thin films of molybdenum nitride with a filled β-Mn-type structure. A series of Fe_(2-x)Pd_xMo_3N (x = 0.15, 0.32, and 0.54) thin films are grown epitaxially with the (110) orientation on c-plane sapphire substrates by reactive magnetron sputtering, and their structural, magnetic, and transport properties are investigated. Studies using the Topological Hall effect and Lorenz transmission electron microscopy imaging for films with x = 0.32 identified the existence of two types of skyrmion phases with a size as small as 60 nm; one is a dense skyrmion phase at temperatures below 100 K, and the other is an isolated skyrmion phase in a higher temperature range to well beyond room temperature. These epitaxial thin films in the family of molybdenum nitrides open the way for the study of skyrmions, manipulation of their properties, and the exploration and optimization for skyrmion-based applications.