Atomic disorder induced modification of magnetization in MnCrVAl*

Spin-gapless semiconductors (SGS) are recently discovered materials which are characterized by a zero band gap in one spin channel and a finite band gap in the other channel. We have investigated the physical mechanisms behind experimentally observed magnetization reduction in a potential SGS compound MnCrVAl by analyzing various atomic disorder schemes. We show that depending on the degree of disorder, exchanging atomic positions between Mn/Cr and V/Al leads to reduced total magnetization due to either spin flip, or vanishing spin magnetic moments. The latter is attributed to the itinerant character of magnetism, and to the frustration of antiferromagnetic exchange interactions. Besides, we demonstrate that in certain disordered structures the spin polarization of MnCrVAl significantly increases, reaching the half-metallic state. We also show that antisite disorder does not result in significant reduction of magnetization. These findings may contribute to understanding the role of atomic disorder on magnetic properties of materials with potential applications in spin-based electronics.