中文摘要：

通过X射线衍射和磁性测量手段研究了由Cr,Mn,Co,Ni原子替代LaFe11.5Si1.5化合物中的Fe原子,对化合物结构、磁性与磁热效应的影响。结果表明：替代后的所有化合物的主相均为NaZn13型立方结构并存在杂相,衍射数据精修图表明杂相分别为1.3%的α-Fe相和2.5%的LaFeSi相。Cr,Mn和Ni的替代Fe使LaFe11.5 Si1.5化合物的居里温度与饱和磁化强度下降,而Co的替代化合物的居里温度与饱和磁化强度且增加。所有的替代均使化合物的热滞下降。对Cr,Mn,Fe,Co,Ni替代Fe的化合物在0～5.0 T的磁场下最大磁熵变-ΔSm分别为23.8,19.8,26.4,20.0和25.9 J.（kg.K）-1。

英文摘要：

The effects of substitution of Fe by Cr,Mn,Co and Ni on the structure,magnetic and magnetocaloric properties of LaFe11.5Si1.5 were investigated by means of X-ray diffraction and magnetic measurements.The results showed that the compounds investigated mainly crystallized in NaZn13-type cubic structure.For Cr,Mn,Co and Ni substituted compounds,the impurity phases were mainly 1.3% α-Fe and 2.5% LaFeSi,both Curie temperature and saturation magnetization decreased with these impurity phases in LaFe11.5Si1.5,while increased for Co-substitution.The thermal hysteresis reduced for all substitution.The maximum value of magnetic entropy change ｜ΔSm｜ for a magnetic field change of 0~5 T was about 23.8,19.8,26.4,20.0 and 25.9 J ·（kg · K）-1 for T=Cr,Mn,Fe,Co and Ni,respectively.