Magnetotransport properties of Fe48Mn24Ga28 Heusler alloys

Magnetotransport properties of an Fe48Mn24Ga28 Heusler-based ferromagnetic shape memory alloy are tracked in a temperature interval that covers both martensitic and austenitic phases. A large temperature hysteresis indicative of a coupled magnetostructural transition from ferromagnetic martensite to paramagnetic austenite is observed on the temperature dependencies of magnetization and electrical resistivity. The temperature dependency of the anomalous Hall-effect coefficient in Fe48Mn24Ga28 cannot be described in terms of skew scattering, side-jump, and intrinsic mechanisms of the anomalous Hall-effect theory. The Hall-effect resistivity in the martensitic state is smaller, but is of the same order of magnitude as in the case of the giant Hall effect in a half-metallic Co2MnAl. Specific features of the temperature dependencies of magnetization, resistivity, magnetoresistance, and ordinary and anomalous Hall-effect coefficients are discussed and the possible routes for increasing Hall-effect resistivity are suggested.