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系统研究了室温下Tb0.3Dy0.7(Fe1?xAlx)1.95(x=0,0.05,0.1,0.15,0.2,0.25,0.3,0.35)合金中金属Al替代Fe对晶体结构、磁致伸缩、内禀磁致伸缩、各向异性和自旋重取向的影响.结果发现,x<0.4时,Tb0.3Dy0.7(Fe_(1-x)Al_x)1.95完全保持MgCu2立方Laves相结构,晶格常数a随Al含量x的增加而增大.磁致伸缩测量发现,随着替代量x的增加磁致伸缩减小,x>0.15时超磁致伸缩效应消失;x<0.15时磁致伸缩在低场下(H≤40kA/m)有小幅增加,高场下迅速减小,而且易趋于饱和,说明添加少量Al有助于减小磁晶各向异性.内禀磁致伸缩λ111随Al替代量x的增加大幅度降低.M?ssbauer效应表明,Tb0.3Dy0.7(Fe1?xAlx)1.95合金的易磁化方向随成分和温度在{110}面逐渐偏离了立方晶体的主对称轴,即自旋重取向.室温下,当x=0.15时,Tb0.3Dy0.7(Fe1?xAlx)1.95合金中出现了少量非磁性相;x>0.15时,合金完全呈顺磁性;而77K温度下x=0.2时合金仍然呈磁性相.在室温和77K温度时,超精细场Hhf均随Al元素的增加而减小,而同质异能移IS随Al元素的增加而增加.
The effects of metal Al substitution for Fe on the structure of Tb0.3Dy0.7 (Fe1? XAlx) 1.95 (x = 0,0.05,0.1,0.15,0.2,0.25,0.3,0.35) alloys at room temperature were studied systematically. The results show that Tb0.3Dy0.7 (Fe_ (1-x) Al_x) 1.95 completely retains MgCu2 cubic Laves phase structure when x <0.4, the lattice constant a increases with increasing Al content.Magnetostrictive measurements show that the magnetostriction decreases with the substitutional amount x, and the magnetostriction disappears when x> 0.15; the magnetostriction decreases with x <0.15 (H≤40kA / m) increased slightly and decreased rapidly in high field, and tends to be saturated, indicating that the addition of a small amount of Al helps to reduce the magnetocrystalline anisotropy.The intrinsic magnetostriction λ111 with Al substitution M x ssbauer effect indicates that the easy magnetization direction of Tb0.3Dy0.7 (Fe1? XAlx) 1.95 alloy gradually deviates from the main axis of symmetry of the cubic crystal in {110} plane with composition and temperature, that is, At room temperature, a small amount of non-magnetic phase appeared in Tb0.3Dy0.7 (Fe1? XAlx) 1.95 alloy when x = 0.15 at room temperature. When x> 0.15, the alloy was completely paramagnetic. At 77K, x = 0.2 when the alloy is still magnetic phase And the temperature at 77K, hyperfine field Hhf increased with Al element is reduced, while the isomer shift IS with increasing Al element increases.