The multiple magnetic transitions and magnetic entropy change of RGa compounds

Abstract

<p indent=0mm>Magnetic refrigerant materials working at middle and low temperature range have drawn much attention because they can be used for gas liquefaction such as oxygen, nitrogen, hydrogen and helium. It is continuous goal for researchers to explore and obtain magnetic refrigerant materials with large magnetic entropy change, wide refrigerant temperature span, high refrigeration capacity and large adiabatic temperature change. RGa family is a kind of rare earth based intermetallic compounds with abundant magnetic transitions. This paper reviews the results of low-temperature order-order magnetic transition, high-temperature order-disorder magnetic transition and magnetic entropy change for PrGa, NdGa, SmGa, GdGa, TbGa, DyGa, HoGa, ErGa, TmGa and Er₁₋_{<italic>x</italic>}Gd_{<italic>x</italic>}Ga compounds. The low-temperature order-order magnetic transition includes spin reorientation transition, ferromagnetic to modulated antiferromagnetic transition and cone-ferromagnetic to cone-ferromagnetic transition. There are several peaks on the magnetic entropy change curves which provide ideas for designing magnetic refrigerant materials with large temperature span. The characteristics of magnetic transitions and magnetic entropy change for RGa compounds are analyzed, the dependency relationship together with related physical mechanism are expounded and the possible research interests in the future are discussed.