A magnetic refrigerator exploits the magnetocaloric effect, which is broadly defined as the tendency of certain magnetic materials to change their temperature when placed in a magnetic field. There is a great interest in the commercialization of magnetic refrigerators due to the fact that they are significantly more environmentally friendly and energy efficient than common vapor-compression based refrigerators. However, before magnetic refrigerators can be commercialized, magnetic materials with desirable properties such as cost-efficiency and a large magnetocaloric effect at room temperature must be developed. In this presentation, a series of four alloys belonging to the Mn0.5+xFe0.5Ni1−xSi0.94Al0.06 family are discussed. The alloys were prepared by performing stoichiometric calculations and weighing the constituent elements, followed by vacuum arc melting and annealing. Structural properties were investigated by powder X-ray diffraction. The x = 0 and x = 0.05 samples were found to have a hexagonal structure at room temperature, whereas the x = 0.10 and x = 0.15 samples were found to have an orthorhombic structure. These phases are found in similar alloys known to exhibit a giant magnetocaloric effect at room temperature, which confirms both the potential of the compounds for magnetic refrigeration and the relative purity of our samples. Our next steps involve further structural analysis to find lattice constraints and other crystallographic parameters, and then investigation into the specific magnetic properties of the alloys such as magnetic transition temperature and thermal hysteresis. This research is relevant to my intended career in materials science research and development, as it allows me to develop key technical skills related to the synthesis, characterization, and analysis of metallic alloys for broad technical applications.
Author: Kyra Stillwell
Faculty Advisor: Mahmud Khan, Physics
Graduate Student Advisor: Ranjit Chandra Das, Physics
You must be logged in to post a comment.