Excellent cryogenic magnetocaloric performances in ferromagnetic Sr₂GdNbO₆ double perovskite compound

The solid state magnetic cooling (MC) method by utilizing the magnetocaloric effect (MCE) has been recognized as an environmentally friendly and energy efficiency technology. A huge gap between the developing of MCE materials and the practical MC applications still exists at present. In this work, a combination theoretical and experimental investigation of the Sr₂GdNbO₆ compound with a typical orthorhombic double perovskite (DP) type structure in terms of structural, magnetic and MCE properties have been reported. Ferromagnetic (FM) interaction with large magnetic moment at ground state has been confirmed in Sr₂GdNbO₆ DP compound. Excellent MCE performances at cryogenic have been realized in Sr₂GdNbO₆ DP compound which is accompanied by a second-ordered type magnetic transition from paramagnetic to FM state. The observed large MCE parameters make the Sr₂GdNbO₆ DP compound attractive for practical cryogenic MC applications.