Electronic structure and large magnetocaloric effect in GdVO4 nanocrystals

•Electronic structure and magnetocaloric effect (MCE) studies of GdVO4 nanocrystals.•Large MCE with |ΔSmax| = 49 J/kg K at 2.6 K and RCP(RC)= 332 (239) J/K.•MCE of GdVO4 comparable that of other potential materials usable to liquefy helium and hydrogen.•First-order transition and short-range order related to antiferromagnetism, surface spin disorders, and spin flop. A sample of gadolinium orthovanadate (GdVO4) nanocrystals crystallizing in the I41/amd tetragonal structure has been synthesized by a hydrothermal method. Electron microscope analyses have revealed the sample comprising gravel- and rod-shaped nanoparticles with the sizes of 30–80 nm. The magnetocaloric (MC) assessments upon the set of initial magnetization data have indicated a large MC effect in GdVO4 nanocrystals. Under a magnetic-field change of 60 kOe, the largest magnetic-entropy change and relative cooling power are about 49 J/kg·K at 2.6 K and 332 J/K, respectively, which are comparable to the MC behaviors of their bulk samples. Such large MC values together with almost no magnetic hysteresis make GdVO4 an excellent candidate for cryogenic magnetic refrigeration at low temperatures as liquefying helium and hydrogen. Analyzing in detail the magnetization and magnetic-entropy data versus the temperature and magnetic field, we have found GdVO4 nanocrystals having short-range magnetic order, which is associated with the anti-ferromagnetic order, surface spin disorders, and spin flop.