Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

We report a large exchange-bias effect after zero-field cooling the new tetragonal Heusler compound Mn₂PtGa from the paramagnetic state. The first-principles calculation and the magnetic measurements reveal that Mn₂PtGa orders ferrimagnetically with some ferromagnetic inclusions. We show that ferrimagnetic ordering is essential to isothermally induce the exchange anisotropy needed for the zerofield cooled exchange bias during the virgin magnetization process. The complex magnetic behavior at low temperatures is characterized by the coexistence of a field-induced irreversible magnetic behavior and a spin-glass-like phase. The field-induced irreversibility originates from an unusual first-order ferrimagnetic to antiferromagnetic transition, whereas the spin-glass-like state forms due to the existence of antisite disorder intrinsic to the material.