La_(0.85)Ce_(0.15)Fe_(11.4)Si_(1.6)合金磁热效应的间接测量和直接测量

Indirect and Direct Measurement of Magnetocaloric Effect in La_(0.85)Ce_(0.15)Fe_(11.4)Si_(1.6) Alloys

采用X射线衍射和磁性测量等手段研究了金属间化合物La0.85Ce0.15Fe11.4Si1.6的结构和磁热效应。结果表明,该化合物在211K附近经历了从铁磁到顺磁的二级相变。当外加磁场从0T增加到1.5T时,磁熵变为4.98J/kg.K。通过直接测量的方法得到了La0.85Ce0.15Fe11.4Si1.6化合物在211K的1.0T^0T退磁场的绝热温变为1.1K。大的熵变值和绝热温变表明La0.85Ce0.15Fe11.4Si1.6化合物很有潜力作为相应温区的磁制冷材料。

Crystal structure and magnetic properties of Lao.La0.85Ce0.15Fe11.4Si1.6 were investigated by x- ray powder diffraction and magnetic measurements, which undergoes a second- order transition at 211K from the ferromagnetic to paramagnetic state. The magnetic entropy ctumge upon a field increase from 0T- 1.5T is 4.98J/kg· K. The adiabatic temperature change obtained via direct measurements： reaches 1.1K under a field change from 1.0T - 0T. The large values of entropy change and adiabatic temperature change confirmed the large potential of present compound as a magnetic refrigerant in the corresponding temperature range.