Structural, Magnetic, and Magnetocaloric Properties in Rare Earth Orthochromite (Sm, Nd, and La)CrO₃ for Cooling Product

Polycrystalline phase of SmCrO₃, NdCrO₃, and LaCrO₃ orthochromites was synthetized with solid-state reaction method. The pure orthorhombic phases with space group Pnma have been confirmed by X-ray diffraction. In addition, the FTIR spectroscopy proved the formation Sm–O, Nd–O, and La–O bonds in SmCrO₃, NdCrO₃, and LaCrO₃ respectively, and Cr–O and Cr–O–Cr bonds in all our samples. The particles morphology and composition results were obtained using the scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). The Quantum Design XL-SQUID magnetometer is used in order to determine the magnetic transition type and transition temperature for each sample. We found that our samples exhibit a transition at 195 K, 65 K, and 35 K for SmCrO₃, NdCrO₃, and LaCrO₃ respectively. The magnetic entropy change (∆S_m), as the key parameter to evaluate the magnetocaloric effect, is calculated. Our samples present a ∆S_m in the range of 0.11 and 0.25 J kg⁻¹ K⁻¹ for an external magnetic field of 5 T.