Executive Summary : | Solid State refrigeration offers cost-saving, high efficiency, and environmental-friendly solutions for cooling. However, researchers are exploring promising caloric materials, such as mixed spinel ferrites, which exhibit magnetocaloric effect (MCE) or electrocaloric effect (ECE) near the magnetic or electric phase transition temperature. Shape memory Heusler alloys (SMHA) are potential candidates for multicaloric applications, but have drawbacks such as raw material and fabrication costs, toxicity, stability, corrosion, and hysteresis. Mixed spinel ferrites are more attractive due to their second-order phase transition, stability, non-toxic composition, synthesis route, and rich electric and magnetic properties. The proposed series of materials Mn1-xMxFe2-yNyO4 (M=Cu,Zn) and (N=V,Zr,Sn,Ti, Gd,Dy,Eu,Er) can be valuable for magnetic/electric refrigeration and energy storage applications. Spinel structures are highly suitable for chemical substitutions and can accommodate a wide variety of divalent/trivalent/tetravalent magnetic/non-magnetic cations at their tetrahedral and octahedral sites. The optimized values of x and y content will tune the broad phase transition near room temperature and provide wide variation in their combined electric and magnetic properties, making them suitable for multicaloric refrigerants. The substitution of transition metals (Ti,V,Zr,Sn,) and rare earth elements (Eu,Gd,Dy,Er) in Mn-Zn & Mn-Cu ferrites at the Fe-site can introduce spin freezing, spin-glass, and relaxor behavior, increasing the material's useful parameter relative cooling power (RCP) for magnetic refrigeration. Magnetic V substitution can enhance energy storage properties. |