Effect of hydrostatic pressure on the magnetic, exchange bias and magnetocaloric properties of Ni45.5Co2Mn37.5Sn15

Abstract

In this study, we report the effect of hydrostatic pressure (P) and magnetic field (H) on the magnetization, magnetocaloric effect and exchange bias in a Ni45.5Co2Mn37.5Sn15 Heusler alloy. At ambient pressure, the martensitic transition temperature (TM) shifts to lower temperatures with a rate of dTM/dμ0H ∼ 3.29 K/T. On the other hand, TM increases rapidly to higher temperatures with dTM/dP ∼31.90 K/GPa when hydrostatic pressure is applied. The peak value of magnetic entropy change due to change in magnetic field of 5 T is found to decrease with increasing pressure. Although, the relative cooling power (RCP) increases from ∼189 Jkg-1 to ∼ 204 Jkg-1 during cooling cycle, a significant drop in net RCP is obtained from the measurements under heating cycle. The coercivity of the sample at a given temperature merely changes, but the exchange bias effect is improved by applying pressure.