Metamagnetic transition and reversible magnetocaloric effect in antiferromagnetic DyNiGa compound**Project supported by the National Natural Science Foundation of China (Grant Nos. 51701130 and 51925605), the Natural Science Foundation of Tianjin, China (Grant Nos. 18ZXCLGX00040 and 15JCZDJC38700), and the National Key Research and Development Program of China (Grant Nos. 2019YFA0704900, 2019YFA0705000, 2019YFA0705100, 2019YFA0705200, and 2019YFA0705300).

Abstract

Rare-earth (R)-based materials with large reversible magnetocaloric effect (MCE) are attracting much attention as the promising candidates for low temperature magnetic refrigeration. In the present work, the magnetic properties and MCE of DyNiGa compound with TiNiSi-type orthorhombic structure are studied systematically. The DyNiGa undergoes a magnetic transition from antiferromagnetic (AFM) to paramagnetic state with Néel temperature TN = 17 K. Meanwhile, it does not show thermal and magnetic hysteresis, revealing the perfect thermal and magnetic reversibility. Moreover, the AFM state can be induced into a ferromagnetic state by a relatively low field, and thus leading to a large reversible MCE, e.g., a maximum magnetic entropy change (−ΔSM) of 10 J/kg⋅K is obtained at 18 K under a magnetic field change of 5 T. Consequently, the large MCE without thermal or magnetic hysteresis makes the DyNiGa a competitive candidate for magnetic refrigeration of hydrogen liquefaction.