The Effects of the Size of Sample and Rate of Magnetic Field on the Hysteresis of Lafesi-Based Magnetic Refrigeration Materials

Abstract

The paper examines the magnetic properties and hysteresis of La-Fe-Si-based magnetic refrigeration materials with different sizes and magnetic field rates. It is observed that both the thermal hysteresis and magnetic hysteresis increased as the sample size increased due to the lower response of large-sized samples to thermal effects. A double peak in the up-field magnetic entropy change is observed in the magnetic entropy change curve of the 2*2*2 sample, which can be improved by calculating down-field magnetic entropy change and average magnetic entropy change. The size of samples has little effect on the magnetic entropy change. Moreover, the magnetic hysteresis increases and then decreases with temperature increase and reaches the maximum near TC, which is similar to the magnetic entropy change. There is a correlation between the magnetic hysteresis and the magnetic entropy change. However, there is little difference between the values of maximum magnetic entropy change at different magnetic field rates and no obvious correlation with the magnetic field rate. The size of samples and the magnetic field rates impact hysteresis but less so on the magnetic entropy changes. This research enhances our understanding of the factors influencing lag and contributes to the development of magnetic refrigeration materials.

Keywords: La-Fe-Si, magnetocaloric effect, magnetic field rates, hysteresis, magnetic entropy change