Strain glass versus antisite disorder induced ferromagnetic state in Fe doped Ni-Mn-In Heusler martensites

摘要

Fe doping in Ni2Mn1.5In0.5 results in suppression of the martensitic phase via two contrasting routes. In Ni2Mn1.5 - xFexIn0.5, the martensitic phase is converted to a strain glassy phase, while in Ni2 - yFeyMn1.5In0.5, a cubic ferromagnetic phase results at the expense of the martensite. Careful studies of magnetic and structural properties reveal the presence of the impurity gamma-(Fe,Ni) phase as the reason for the emergence of non-ergodic strain glassy phase when Fe is sought to be doped at Y/Z (Mn) sites of X(2)YZ Heusler alloy. Whereas attempts to dope Fe in the X (Ni) sublattice result in an A2 type antisite disorder that promotes a ferromagnetic ground state.