Interface-Induced Conventional and Inverse Magnetocaloric Properties of GdFeCo Thin Films

Abstract

A transformation from conventional to enhanced inverse magnetocaloric effect is being investigated in ferrimagnetic Gd₃₅Fe₅Co₆₀ thin films at a lower temperature than the magnetic ordering temperature. RF magnetron sputtering is utilized to deposit 80 nm GdFeCo thin film sandwiched between Pt or Ta layers (Pt/GdFeCo/Pt and Ta/GdFeCo/Ta) on a Si (100) substrate to achieve optimal interfacial effects. A significant change in magnetic compensation temperatures (T_comp) and magnetic ordering is noticed. T_comp observed at 324.1 K for the Pt structure rises to 389.7 K for the Ta structure. The ferrimagnetic to paramagnetic phase transition, Curie temperature (T_c), is found at 586.8 and 664.3 K for Pt and Ta structures, respectively. The isothermal entropy change (ΔS_M) is estimated by applying 15 kOe in a wide temperature range (100 K < T < 750 K). The Pt structure shows maximum conventional and inverse magnetocaloric entropy changes (ΔS_M) of 1.09 and 0.78 J/kg K, respectively. The Ta structure transforms from conventional to inverse magnetocaloric entropy change with a maximum of 1.08 J/kg K at 15 kOe, which is higher than many thin films reported. These findings not only provide a deeper understanding of the interplay between interface interactions and magnetic dynamics but are also helpful in designing multilayered structures with enhanced magnetocaloric properties.