【摘要】 用电弧熔炼法制备了LaY0.1Fe11.4T0.1Si1.5(T=Cr,Mn,Fe,Co,Ni)系列合金。室温XRD分析与SEM成分分析表明,该系列合金中除存在一个明显的杂相峰(富La相,P4/nmm)和α-Fe相外,主相为NaZn13型立方相。除T=Cr外,Fe位原子替代使合金的晶格常数随着替代原子T的原子半径的减小而减小。磁性测量表明,该系列合金除T=Mn以外,随着替代原子T的原子半径减小,合金的居里温度(TC)有增加的趋势。在外磁场变化ΔB=1.5T时,利用Maxwell方程计算得出,该系列合金磁熵变最大值分别为5.1,13.0,20.7,12.7和7.4J·kg-1·K-1。由此可以看出,T=Fe时合金的磁熵变最大值最大,且该系列合金的磁熵变峰值随着外磁场增加向高温区不对称展宽;TC以上磁场引起的变磁转变是磁熵变峰值不对称展宽的原因。更多还原

【Abstract】 The LaY0.1Fe11.4T0.1Si1.5(T = Cr,Mn,Fe,Co,Ni) alloys were prepared by arc melting.XRD analysis and SEM component analysis show that the LaY0.1Fe11.4T0.1Si1.5(T = Cr,Mn,Fe,Co,Ni) alloys consist of the NaZn13-type cubic phase,minor amount of La-rich phase(P4/nmm) and α-Fe phase.The substitution for Fe site leads to lattice parameter of alloys decrease with decreasing of the atom radius of substitution atom T(except for T = Cr).Magnetic measurement indicates that the Curie temperature of the alloys increases with decreasing of the atom radius of substitution atom T(except for T = Mn).Magnetic entropy changes-ΔSm were calculated from the isothermal magnetizations by the Maxwell relation.The maximum values of the magnetic entropy change are 5.1,13.0,20.7,12.7 and 7.4J·kg-1·K-1,respectively.It should be noticed that the alloy has the largest magnetic entropy change for T = Fe.The largest value of magnetic entropy change extends to the high temperature zone when increasing the external fields,which is due to the IEMT above Criue temperature.更多还原