Negative spin polarization of Mn2VGa Heusler alloy thin film studied in current-perpendicular-to-plane giant magnetoresistance devices

Mn
2
VGa (MVG) ferrimagnetic Heusler alloy possesses negative spin polarization, meaning that the spin direction of the spin-polarized conduction electron is the opposite of the magnetization direction. This characteristic is technologically important because it can increase freedom in the structures of spintronics devices and improve their performance. We fabricated current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) devices consisting of MVG/Ag/CoFe by sputter deposition and demonstrated negative MR, which provided evidence of negative spin polarization of MVG. The observed negative MR ratio reached -1.3%, the highest value among the reported negative MR in CPP-GMR devices. This result suggests relatively high negative spin polarization of MVG.