MAGNETOSTRICTION OF TRANSITION-METAL-METALLOID GLASSES - TEMPERATURE-DEPENDENCE
MAGNETOSTRICTION OF TRANSITION-METAL-METALLOID GLASSES - TEMPERATURE-DEPENDENCE
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DOI：
10.1103/physrevb.18.930
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发表时间：
1978-01-01
影响因子：
3.7
通讯作者：
OHANDLEY, RC
中科院分区：
文献类型：
--
作者：
OHANDLEY, RC
研究了不同（FeCoNi）80 B 20玻璃的线性饱和磁致伸缩系数λ s随温度的变化。在4.2 K范围内，Fe 80 B 20、Co 40 Ni 40 B 20和Ni 50 Fe 30 B 20的磁致伸缩符合Callen和Callen关于单轴应变对称性的单离子各向异性的理论，λ s（T）λ s（0）= I^ 5 2（X）<$I 5 2（X）I 1 2（X）其中I 3 2（X）<$m（T）为约化磁化强度。在富钴（FeCo）80 B 20玻璃中观察到的磁致伸缩的异常温度依赖性归因于正的两离子（各向异性交换）项加上更强的负的单离子（晶场）项的组合。由于主导单离子机制的符号变化，在三角形Fe-Co-Ni（B 20）图的Co-Ni侧沿着出现λ s的符号变化。这种符号的变化是由于费米能态的轨道特征从钴或镍的3d ↓能带的顶部到铁的3d ↓能带的底部发生了变化。
Linear, saturation magnetostrictions λ s of a variety of (FeCoNi) 80 B 20 glasses have been studied as a function of temperature. Magnetostrictions over the range 4.2 K≲ T≲ T C for selected glasses, Fe 80 B 20, Co 40 Ni 40 B 20, and Ni 50 Fe 30 B 20, are shown to follow reasonably well the theory of Callen and Callen for single-ion anisotropy of uniaxial-strain symmetry, ie, λ s (T) λ s (0)= I^ 5 2 (X)≡ I 5 2 (X) I 1 2 (X) with I 3 2 (X)≡ m (T), the reduced magnetization. The anomalous temperature dependence of the magnetostriction observed in the cobalt-rich (FeCo) 80 B 20 glasses is attributed to the combination of a positive two-ion (anisotropic-exchange) term plus a stronger, negative, one-ion (crystal-field) term. A change of sign in λ s occurs along the Co-Ni side of the triangular Fe-Co-Ni (B 20) diagram due to a change in sign of the dominant single-ion mechanism. This sign change results from a change in the orbital character of the states at the Fermi energy as it passes from the top of the cobalt or nickel 3 d↓ band to the bottom of the iron 3 d↓ band.