Spin-glass mediated large exchange bias and coercivity in hexagonal Mn1+xCu1−xGa (x = 0.3–0.5) alloys

Abstract

Ni2In-type MnMX alloys possess interesting noncollinear magnetic structures that may embed a variety of physical phenomena. In this work, magnetic and electrical transport properties of pure Ni2In-type structure Mn1 +xCu1−xGa (x = 0.3–0.5) alloys are investigated systematically. A cluster spin-glass phase is identified below the Curie temperature by magnetization and ac susceptibility measurements in x = 0.5 sample. Mediated by the exchange interaction between Mn-Mn clusters, significant exchange bias effect and coercivity are established, in which a giant exchange bias field of up to 0.323 T is observed in x = 0.5 sample. The exchange bias effect and coercivity, as well as the anomalous Hall effect are found to be greatly tuned via field cooling process. The large EB and coercivity identified in Mn–Cu–Ga alloys make them potentially applied in rare-earth-free magnets and spintronic devices.