Pressure effects on magnetic and magnetocaloric properties of GdCo ₂B ₂

The magnetic and magnetocaloric properties of GdCo ₂B ₂ have been studied under hydrostatic pressures up to 1.27 GPa. The compound undergoes a paramagnetic to ferromagnetic transition at 22.2K and a ferromagnetic to antiferromagnetic transition at 13K with decreasing temperature. The effects of hydrostatic pressure are as follows: it is raises TC and lowers TN. The antiferromagnetic (AFM) phase is completely suppressed under 1.27 GPa, and thus the order of magnetic phase transition changes from first order to second order gradually with increasing pressure. With a field change of 5 T, the values of maximum magnetic entropy change are evaluated to be 17.1, 16.85, and 16.4 J kg ^-1 K ^-1 for P = 0, 0.73, and 1.27 GPa, respectively. The hydrostatic pressure effects on magnetic transition and MCE are discussed.