Structural and magnetic properties of the V₂CoAl Heusler alloy

Within the field of spintronics, there are attempts to create materials such as half-metals with Curie or Neel temperatures above room temperature, 100% spin polarization, and favorable magnetoresistance properties. Heusler alloys in particular have shown promising results in the search for a material with these properties. To further explore this group of materials, we have synthesized and analyzed the V₂CoAl alloy. Our first-principle calculations show that this material is near-half-metallic with a spin-polarization of 96.3%, making it a good candidate for study. Bulk samples were prepared with an arc melter in a copper hearth under an inert atmosphere and were either kept as prepared or were annealed at 700°C for various time periods. These samples were then investigated using X-Ray Diffraction to observe crystal structure in addition to a vibrating sample magnetometer to measure temperature and magnetic field dependence of magnetization. This alloy usually crystallizes in an A2-type disordered structure, but given the right annealing conditions, a B2-type disordered structure can be obtained. This material has also shown signs of antiferromagnetic ordering at low temperatures. These results could be used to further inform the search for room-temperature half-metals for use in spintronics.