Effect of Ti doping on the phase transitions, magnetocaloric effect, and exchange bias in Ni43Mn46Sn11−xTix Heusler alloys

Abstract

In this work, we systematically studied the influence of Ti doping on the crystal structure, martensitic transition, magnetocaloric effect, and exchange bias in Ni43Mn46Sn11−xTix alloys. With the increase of Ti concentration, the martensitic transformation temperature increases gradually due to the effect of lattice contraction, and the ferromagnetic ordering windows in the martensitic and austenitic regions are closed at x = 1 and x = 2, respectively. This study demonstrates that relatively large magnetic entropy changes can be obtained around the paramagnetic-paramagnetic martensitic transformation under high magnetic field. Another effect of Ti doping is the enhancement of antiferromagnetic interaction, which resulting in the transformation of ground state from reentrant-spin-glass to canonical spin-glass for x⩾1. The zero-field-cooled exchange (ZEB) was realized in the composition range of 1⩽x⩽4, of antiferromagnetic interactions is a viable way to achieve ZEB in NiMn-based Heusler alloys.