Coexistence of reentrant-spin-glass and ferromagnetic martensitic phases in the Mn2Ni1.6Sn0.4 Heusler alloy

Abstract

A giant exchange bias field of up to 1170 Oe was observed in the Mn2Ni1.6Sn0.4 Heusler alloy. A reentrant spin glass phase and a ferromagnetic martensitic phase coexist below the blocking temperature as confirmed by dc magnetization and ac susceptibility measurements. Exchange bias in Mn2Ni1.6Sn0.4 is thought to originate from the interface exchange interaction between the reentrant spin glass phase and the ferromagnetic martensitic phase. X-ray diffraction and selected area electron diffraction results demonstrate that excess Mn atoms occupy Ni and Sn sites randomly. In this way, Mn-Mn clusters are formed and constitute the reentrant-spin-glass phase.

Phase stability and magnetic-field-induced martensitic transformation in Mn-rich NiMnSn alloys

“…18 Ma et al further confirm the coexistence of the short-range FM order RSG phase and the long-range FM order martensitic phase at low temperature in Mn 2 Ni 1.6 Sn 0.4 alloy. 19 In Ni 50-x Mn 41+x Sn 9 alloys, the similar spin-glass-like state may occur and account for the split between the FC and ZFC M(T) curves.…”

Giant spontaneous exchange bias triggered by crossover of superspin glass in Sb-doped Ni50Mn38Ga12 Heusler alloys

“…The Mn-Mn exchange interaction within the regular Mn sublattices and the Mn-Mn exchange interaction between the regular Mn sublattice and the Z sublattice correspond to the FM and the AFM phases, respectively91415. The competition between the FM and the AFM phases can generate frustrated magnetic behavior and thereby lead to the SEB effect.…”

Effect of interfacial pinning on the thermo-remanent magnetization of disorder Mn50Ni38.5Sn11.5 alloy

“…The behaviour of ZFCW M(T) is quite similar to other Heusler alloy systems where the magnetization initially rises slowly with the temperature due to the competition between thermal energy and anisotropy of locked spins/clusters up to exchange bias (EB) blocking temperature (T ⁎ ). Beyond T ⁎ the magnetization increases rapidly up to T f due to defreezing of spins/clusters moments and thereafter the increase of temperature leads to FM PM ⟶ type magnetic transition at Curie temperature of martensite phase (T C M ) and with further increase of temperature we observe the reverse MT [11,18]. In FCW [curve(ii)], magnetization decreases slowly with the increase of temperature and eventually merged with ZFCW M(T) around T irr ¼155 K. Thereafter, FCW follows the same path as ZFCW M(T).…”