Origin of low magnetic moment in quaternary Heusler alloy NiFeTiGa

Ferromagnetic materials that exhibit long range magnetism with a net-zero or very low ordered moment have great technological demand. Only a few compounds are known to possess such important characteristics. A new quaternary Heusler alloy NiFeTiGa has recently been reported to form with atomic disorder and exhibit ferromagnetic ordering with very low saturation magnetic moment. To check the possible occurrence of low-moment ferromagnetism in this compound, we have re-investigated the structural and magnetic properties of NiFeTiGa, using x-ray diffraction and various dc- and ac-magnetization techniques. Our structural analysis of a single phase polycrystalline sample remains inconclusive about the nature of atomic disorder in the system. Most importantly, our investigation indicates that the low saturation moment is arising out due to dominating metastable character of spins, although the presence of a weak ferromagnetic contribution can also not be ruled out completely.