Study of Magnetic and Magnetocaloric Properties of Fe50 – xCuxNi25Ti25 Alloys

Using a combined density functional theory and Monte Carlo approach, we systematically investigated the effect of copper doping on the magnetic and magnetocaloric properties of Fe50 – xCuxNi25Ti25 (x = 0–18.75 at %) alloys. The inverse cubic structure with ferromagnetic ordering was found to be energetically favorable. Exchange interaction analysis revealed a strong ferromagnetic coupling (31.5 meV) in the first coordination sphere between iron atoms located in nonequivalent positions, with copper doping it enhances to 34.4 meV at 12.5 at % Cu. Cu addition reduces the total magnetic moment, Curie temperature, isothermal magnetic entropy and adiabatic temperature changes, ΔSmag and ΔTad. The parent compound Fe50Ni25Ti25 exhibits the highest TC = 700 K and the maximum ΔSmag = –0.25 J kg–1 K–1. Alloying with copper leads to a decrease in ΔTad by 7 times and ΔSmag by 10 times compared to the undoped alloy.