Mn-based hard magnets with small saturation magnetization and low spin relaxation for spintronics

The pursuit of high saturation magnetization is an important area of hard magnetic materials research. However, spintronics requires hard magnets exhibiting small saturation magnetization and low spin relaxation. Mn-based alloys that are composed of Mn and light group III and/or group IV elements exhibit such properties and may belong to a new category of magnetic materials. In this article, we review the magnetic properties of Mn-based hard magnet films. In particular, we focus on low spin relaxation as a new viewpoint for hard magnets, and we discuss the origin of their extraordinary magnetism in terms of their unique electronic structures.