Magnetic properties and enhanced cryogenic magnetocaloric effect in Ti-substituted Gd2CoMnO6 double perovskites

The magnetocaloric effect based on magnetic solid materials shows an important research value in magnetic refrigeration from the perspective of fundamental research and application. In the present work, the monoclinic double perovskites Gd 2 CoMn 1- x Ti x O 6 ( x = 0 - 1.0) were successfully synthesized by a traditional solid-state reaction method. The effects of Ti substitution were experimentally investigated through crystal structure, surface morphology, magnetic behavior and magnetocaloric effect. The magnetic measurement result reveals that the ferromagnetic transition is suppressed substantially by Ti substitution in Gd 2 CoMn 1- x Ti x O 6 . The maximum magnetic entropy change of Gd 2 CoMn 1- x Ti x O 6 is enhanced significantly from 16.64 J∙kg -1 ∙K -1 at x = 0 to 27.16 J∙kg -1 ∙K -1 at x = 1.0 under the magnetic field interval Δ H = 6 T and temperature T = 4 K. A possible mechanism for the enhanced cryogenic magnetocaloric effect is proposed based on the magnetic phase transition. The present work provides an effective approach to enhance the magnetocaloric effect for heavy rare-earth based double perovskites.