中文摘要：

研究了Mn_（1.25）Fe_（0.65）P_（0.5）Si_（0.5-x）B_x（x=0,0.01,0.03,0.04,0.06,0.07）系列化合物的结构及磁性。结果表明,该系列化合物均为Fe2P型六角结构,空间群为P-62m;磁性测量表明该系列化合物都经历了一级相变,并且均存在热滞,但热滞都较小,当硼的原子分数为0.07时,热滞最大值为5K。居里温度随着硼含量的增加,呈现升高的趋势,当硼的原子分数为0.07时,居里温度为325K,而化合物的最大磁熵变呈现下降的规律,当硼的原子分数为0.07时,最大磁熵变为2J/（kg·K）。

英文摘要：

The structure and magnetic properties of Mn_（1.25）Fe_（0.65）P_（0.5）Si_（0.5-x）Bx（x= 0,0.01,0.03,0.04,0.06,0.07）compounds were studied.The XRD results show that the main phase of the compounds is Fe_2P-type hexagonal structure with space group P-62 m.Magnetic measurements indicate that the compounds undergo a first-order phase transition,and the thermal hysteresis is very small,the maximum thermal hysteresis is 5Kfor B=0.07（atom fraction）.With the increase of the content of B,the Curie temperature increases.When the content of B is 0.07（atom fraction）,the Curie temperature is 325 K.and the maximum magnetic entropy is about 2J/（kg·K）for a field change of 1.5T.With the increase of the content of B,the maximum magnetic entropy decreases.