Giant reversible magnetocaloric effect in antiferromagnetic rare-earth cobaltite GdCoO3

Abstract

We have investigated the magnetic properties and magnetocaloric effects in polycrystalline GdCoO3 with a low-spin state of Co3+ ion by magnetization and heat capacity measurements. GdCoO3 shows antiferromagnetic ordering due to the Gd3+ magnetic moments below Néel temperature TN = 3.1 K. This compound exhibits a giant magnetocaloric effect around TN. The maximum value of isothermal magnetic entropy change is 39.1 J/kg K, the peak value of adiabatic temperature change is 19.1 K, and the refrigerant capacity is 278 J/kg for a field change of 0-70 kOe around TN. The large magnetocaloric effect is related to the half-filled 4f electronic state of Gd3+ ions. The giant magnetocaloric effect as well as no hysteresis suggest that GdCoO3 could be a potential refrigerant in low-temperature magnetic refrigeration technology.