Effect of annealing on magnetic and magnetocaloric properties of SmCo3B2 thin films

Abstract

In this study, SmCo3B2 ternary thin films of manifold thickness were fabricated via e-beam evaporation technique. All the as-deposited SmCo3B2 thin films were subjected to electron beam rapid thermal annealing (ERTA). The X-ray diffraction studies showed amorphous nature for all the as deposited thin films and a highly crystalline hexagonal structure for all ERTA subjected thin films. The elemental composition, purity and surface morphology of the samples were analyzed using energy-dispersive x-ray spectroscopy (EDS) and High-resolution Scanning Electron Microscopy (HR-SEM). Furthermore, the study investigates the magnetocaloric properties of SmCo3B2 thin films, with significant changes depending on the thickness and annealing time. The thin films exhibited a magnetic phase transition around the Curie temperature (Tc) within the range of 40–46 K, attributed to the indirect exchange coupling of Sm–Sm sublattice interactions. Moreover, a significant shift in Tc towards higher temperatures with respect to thickness and annealing were observed in both as deposited and ERTA subjected thin films. The Arrot plots in the positive quadrant suggested the second order magnetic phase transition (SOPT) for all the films. The maximum magnetic entropy change (−ΔSm) of 1.172 Jkg−1K−1 accompanied by a relative cooling power of 5.33 Jkg-1 was achieved for 240 nm ERTA subjected thin film under a change in magnetic field of 5T. The study reveals the effect of ERTA and thickness dependent magnetic and magnetocaloric properties of SmCo3B2 thin films.