Giant magnetocaloric properties of Gd-based double perovskite compounds in cryogenic temperature range

Abstract

Magnetic refrigeration technology (MRT) leverages the magnetocaloric effect (MCE) to deliver an innovative, energy-efficient, and eco-friendly cooling solution. The primary challenge in advancing MRT lies in optimizing materials with a robust MCE and developing practical systems for widespread refrigeration and cooling appli cations. In this study, a double perovskite-structured Gd 2 FeCrO 6 (GDFCO) compoundis synthesized following the conventional sol–gel technique and its structural, microstructural, and magnetocaloric properties are examined. The X-ray diffraction (XRD) analysis along with Rietveld refinement, confirms the presence of two coexisting phases, monoclinic structure with P2 1 R /n space group (90.94 %) and minimal amount of trigonal structure with 3 c space group (9.06 %). The average crystallite size, determined from the Williamson-Hall plot, is ~ 120 nm. Field Emission Scanning Electron Microscopy (FESEM) image reveals a homogeneous microstructure with nearly spherical shapes, while Energy Dispersive X-ray Spectroscopy (EDS) verifies the presence and correct proportion of required elements. The compound exhibits two magnetic transition temperatures, with T N1 K and T N2 occurring at ~ 220 at ~ 6 K. Arrott’s plot conforms to the second-order phase transitions (SOPT). A remarkable mag netocaloric effect (MCE) was observed, with a maximum entropy change ( ΔS M ) ~ 38.6 J/kg K and relative cooling power (RCP) ~ 418 J/kg at 4 K with applied magnetic fields of 0–70 kOe. These findings indicate that GDFCO can be a better material for cryogenic magnetic refrigeration, with the potential to advance the field of magnetic cooling technology