Tb_(0.3)Dy_(0.7)(Fe_(1-x)Al_x)_(1.95)合金的磁致伸缩、自旋重取向和穆斯堡尔谱研究  

Magnetostriction, spin reorientation and Mssbauer study of Tb_(0.3)Dy_(0.7)(Fe_(1-x)Al_x)_(1.95) intermetallic compounds

作　　者：郑小平[1] 薛德胜[1] 李发伸[1] 成昭华[2] 吴光恒[2] 沈保根[2] 

机构地区：[1]兰州大学磁学与磁性材料教育部重点实验室,兰州730000 [2]中国科学院物理研究所磁学国家重点实验室,北京100080

出　　处：《物理学报》2002年第4期922-927,共6页Acta Physica Sinica

基　　金：国家自然科学基金 (批准号 :19835 0 5 0 );高等学校重点实验室访问学者基金资助的课题~~

摘　　要：系统研究了室温下Tb0 .3 Dy0 .7(Fe1 -xAlx) 1 .95(x=0 ,0 .0 5 ,0 .1,0 .15 ,0 .2 ,0 .2 5 ,0 .3,0 .35 )合金中金属Al替代Fe对晶体结构、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 .3 Dy0 .7(Fe1 -xAlx) 1 .95完全保持MgCl2立方Laves相结构 ,晶格常量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的增多磁致伸缩减小 ,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≤ 4kA 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λ1 1 1 随Al替代量x的增加大幅度降低 .对于 0≤x <0 .15 ,穆斯堡尔效应表明 ,随Al含量的增加Tb0 .3 Dy0 .7(Fe1 -xAlx) 1 .95合金中发生了自旋重取向 ,易磁化方向经历了 [111]→ [uv 0 ]→ [uvw]的转变 .由相对磁化率随温度的变化关系可以看出 ,Al替代Fe使自旋重取向温度降低 .当x =0 .15时 ,Tb0 .3 Dy0 .7(Fe1 -xAlx) 1 .95合金中出现了少量非磁性相 ;x>0 .15时 。The effect of Al substitution for Fe on the structure, magnetostriction, anisotropy and spin reorientation of a series of Tb 0.3 Dy 0.7 (Fe 1-x Al x ) 1.95 alloys ( x =0, 0.05, 0.1, 0.15, 0.20, 0.25, 0.30, 0.35) at room temperature has been investigated. It was found that all the compositions of Tb 0.3 Dy 0.7 (Fe 1-x Al x ) 1.95 substantially retained the MgCu 2 type C 15 cubic Laves phase structure and the lattice constant increases with increasing x . The substitution of Al increases slightly the magnetostriction in low magnetic field ( H ≤40kA·m -1 ) when x <0.15, however, the magnetostriction decreases sharply, but is saturated more easily with increasing x in a higher applied field and the magnetostrictive effect disappears at x >0.15. The intrinsic magnetostriction λ 111 decreases sharply also with incresasing x . The Mssbauer spectra show that for 0≤ x <0.15 alloys, spin reorientation is present with increasing Al concentration and the easy magnetization direction (EMD) undergoes the transition from [111] to [ u v 0 ] and to [ u v w ]. A small amount of non magnetical phase exists for x =0.15, and the alloys become paramagnetism when x >0 15. The measurements of relative susceptibility indicate that the temperature of spin reorientation decreases with increasing x .

关 键 词：磁致伸缩 立方Laves相 自旋重取向 各向异性 穆斯堡尔谱 Tb0.3Dy0.7(Fe1-xAlx)1.95合金 三元稀土-铁合金 

分 类 号：TG132.27[一般工业技术—材料科学与工程]