Optimizing magnetocaloric properties in (Gd_0.97V_0.03)_1-x/(Gd_0.77 Dy_0.2V_0.03)_x composite

This study theoretically investigates composite materials formulated with (Gd_0.97V_0.03)_1-x/(Gd_0.77Dy_0.2V_0.03)_x (where 0 ≤ x ≤ 1) for their application in Ericsson cycle magnetic refrigerators. Based on theoretical calculations, all compositions with varying x exhibit magnetic transition temperatures near room temperature and demonstrate promising magnetocaloric effects. Among these compositions, the x = 0.45 composite stands out for its exceptional performance. It showcases a constant ΔS of 4 J/kg·K under a moderate 2 Tesla field. This results in a high refrigerant capacity (RC) of 183 J/kg across a broad temperature range (ΔT > 22 K) and a significant adiabatic temperature change (ΔT_ad) of approximately 7 K. These characteristics make the x = 0.45 composite particularly attractive for Ericsson cycle refrigerators for several reasons. Firstly, this composition operates effectively under lower magnetic fields achievable with permanent magnets. This offers a significant cost and complexity advantage compared to traditional systems. Secondly, the x = 0.45 composite boasts an enhanced RC compared to its individual components. This translates to a more efficient cooling process, requiring less material to achieve the desired cooling effect. Finally, this specific composition offers a wider operational temperature range compared to other options. This provides greater flexibility for diverse cooling applications, allowing for adjustments based on specific needs. These findings highlight the potential of tailoring composite composition to achieve a table-like ΔS profile. This targeted design approach paves the way for the development of next-generation magnetic refrigeration technologies operating near room temperature, offering a more efficient and environmentally friendly alternative to traditional vapor compression cooling systems.