Reentrant-spin-glass state in Ni2Mn1.36Sn0.64 shape-memory alloy

The ground-state properties of the ferromagnetic shape-memory alloy of nominal composition Ni2Mn1.36Sn0.64 have been studied by dc magnetization and ac susceptibility measurements. Like few other Ni-Mn based alloys, this sample exhibits exchange bias phenomenon. The observed exchange pinning was found to originate right from the temperature where a steplike anomaly is present in the zero-field-cooled magnetization data. The ac susceptibility study indicates the onset of spin-glass freezing near this steplike anomaly with clear frequency shift. The sample can be identified as a reentrant spin glass with both ferromagnetic and glassy phases coexisting together at low temperature at least in the field-cooled state. The result provides us with a comprehensive view to identify the magnetic character of various Ni-Mn-based shape-memory alloys with competing magnetic interactions.