Importance of site occupancy and absence of strain glassy phase in Ni2−xFexMn1.5In0.5.

Martensitic transition temperature steadily decreases in Ni 2− x Fe x Mn 1.5 In 0.5 and is completely suppressed at x = 0.2. Despite suppression of martensitic transition, Ni 1.8 Fe 0.2 Mn 1.5 In 0.5 does not display the expected strain glassy phase. Instead, a ground state with dominant ferromagnetic interactions is observed. A study of structural and magnetic properties of x = 0.2 reveal that the alloy consists of a major Fe rich cubic phase and a minor Fe deficient monoclinic phase favoring a ferromagnetic ground state. This is exactly opposite of that observed in Ni 2 Mn 1− y Fe y In 0.5 wherein a strain glassy phase is observed for y = 0.1. The change in site symmetry of Fe when doped for Ni in contrast to Mn in the Heusler composition seems to support the growth of the ferromagnetic phase. • Ni 1.8 Fe 0.2 Mn 1.5 In 0.5 despite impurity doping does not display strain glassy phase. • Ni 1.8 Fe 0.2 Mn 1.5 In 0.5 phase separates into major cubic ferromagnetic phase and minor martensitic phase. • Ground state of Ni 1.8 Fe 0.2 Mn 1.5 In 0.5 is exact opposite of strain glassy Ni 2 Mn 1.4 Fe 0.1 In 0.5. • Site symmetry of the dopant atoms plays a role in driving structural and magnetic interactions. [ABSTRACT FROM AUTHOR]