Enhanced antiferromagnetic interaction-induced spontaneous exchange bias in Mn50Ni40Sn10-xTix Heusler alloys

In order to study the conditions of triggering spontaneous exchange bias (SEB) in Heusler alloys, the data of several typical systems in Heusler family are collected and analyzed. It is found that the molecular magnetic moment (MS) is no more than 1μB/f.u. in typical SEB systems. Based on this commonality, a method is put forward by us to trigger SEB in the materials: tuning the relative strength of the ferromagnetic (FM) and the antiferromagnetic (AFM) interactions. In order to verify this view, Mn50Ni40Sn10 with stronger FM interaction and with no SEB effect is chosen as the mother composition, and Sn is substituted with valence-isoelectronic Ti to enhance AFM interaction. It is found that AFM interaction is continuously enhanced with the increase in the Ti content, and SEB is generated and regulated.