Enhanced cryogenic magnetocaloric performance and the existence of short-range magnetic correlations in frustrated diamond geometries

Abstract

The magnetocaloric effect in the cryogenic temperature regime has gained enormous attention due to its application in the field of cryogenic refrigeration technology, which is required for quantum computing, space sciences and basic research activities. In this context, Gd- and Dy-based frustrated systems are considered as promising cryogenic magnetocaloric materials. Hence, in this paper the magnetic and magnetocaloric properties of GdTaO4, GdNbO4 and DyNbO4 are comprehensively investigated. Structural analysis suggests that these compounds crystallize in a monoclinic structure, wherein magnetic ions form an elongated diamond geometry. Analysis of magnetization, heat capacity and field-dependent magnetic entropy changes confirms the presence of short-range magnetic correlations in these compounds. Additionally, a remarkably large magnetic entropy change and relative cooling power are noted. The mechanical efficiency is found to be comparable to (or even better than) those reported for good magnetic refrigerants. Our study suggests that GdTaO4, GdNbO4 and DyNbO4 can be regarded as promising cryogenic magnetic refrigerant materials.