Tailoring exchange bias in reentrant spin glass by ferromagnetic cluster size engineering

Many properties of materials exhibit a heavy dependency on the domain/grain size due to change in interface density. Here, we show that bulk Ni2Mn1+xGa1?x alloys (0.4 < x 0.7), exchange bias (EB) effect appears reentrant spin glass region and magnitude (HEB) depends ferromagnetic (FM) cluster antiferromagnetic (AFM) matrix. It was found HEB first increases then deceases as FM decreases, which shows non-monotonical relationship with size, is similar grain dependence material such mechanical strength metals dielectric permittivity ferroelectric ceramics. Further phase field simulation results repeat this phenomenon illustrate EB can be attributed density FM/AFM interface, provides regulatable extra through Dzyaloshinskii–Moriya interaction. This work method tune reveals mechanism could guide design exchange-bias materials.