Magnetic Properties of FeCrVAl-Based Materials*

Heusler alloys are a type of material composed of multiple transition metals and a p-metal, which generally exhibit desirable electronic properties that could advance the new field of spintronics. We have therefore investigated FeCrVAl-based materials. We first studied the base material FeCrVAl, which we determined to be ferrimagnetic by fitting its magnetization versus temperature graph with the ferrimagnetic Curie-Weiss law. We did not observe a paramagnetic-ferrimagnetic transition above 5 K, which means that the transition, if it occurs, occurs at low temperatures we are unable to access. From the fitting, we were able to obtain molecular field constants of the material. We also investigated FeCr_0.5Mn_0.5VAl, which we determined to be either ferromagnetic or ferrimagnetic based on the observation of a transition from paramagnetic behavior to ferromagnetic behavior at approximately 93 K. The effective magnetic moment of this material was calculated to be about 2.22 Bohr magnetons, which was done by fitting high-temperature data to the Curie-Weiss law. However, the ordered moment from the magnetization-versus magnetic field graph at low temperature was significantly lower than the theoretically calculated value, likely due to a more disordered atomic distribution than assumed theoretically.