Experimental study on coupled caloric effect driven by dual fields in metamagnetic alloy ErCo2

This study presents an experimental investigation of the coupled caloric effect driven by dual-fields in metamagnetic alloy ErCo2 with strong magneto-structural coupling. Magnetic measurements were conducted under different pressures, revealing that the application of hydrostatic pressure stabilizes a small volume of paramagnetism (PM) phase, resulting in a shift of the phase transition temperature towards the low-temperature region. This shift is opposite to the temperature associated with the magnetic field-driven phase transition. As pressure increases, the metamagnetic transition in ErCo2 is suppressed, and the hysteresis disappears. However, the produced cross-coupling caloric effect compensates the decrease in entropy change caused by the disappearance of the metamagnetic transition. As a result, a reversible giant magnetocaloric effect of 46.2 J/(kg·K) without hysteresis is achieved at a pressure of 0.910 GPa. Moreover, we propose that the temperature span of ErCo2 can be significantly widened by optimizing the thermodynamic pathway of the magnetic and pressure fields, overcoming the defect of a narrow temperature range.