MAGNETOELASTIC INTERACTION IN RARE-EARTH SYSTEMS
MAGNETOELASTIC INTERACTION IN RARE-EARTH SYSTEMS
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DOI：
10.1007/bf01325397
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发表时间：
1975-01-01
期刊：
影响因子：
--
通讯作者：
FULDE, P
中科院分区：
文献类型：
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作者：
DOHM, V;FULDE, P
本文提出了稀土体系中旋转不变的自旋-晶格相互作用理论。它表明，旋转不变性的领导秩序，确保只有当旋转相互作用的第一和第二阶的位移是同时包括在自旋晶格哈密顿。旋转的二阶相互作用产生的影响是一样大的线性旋转相互作用。指出对于纯应变相互作用也应该有相应的表述，并计算了稀土系顺磁相的声子绿色函数。研究发现，在外加磁场中，即使对于立方对称，转动相互作用也会引起声子色散和声速的可测量的变化。这些效果原来是相同的数量级作为传统的场相关的应变效应，并从后者有质的不同。以SmSb为例说明了我们的理论结果，并给出了横向声速的定量预测。
A theory of rotationally invariant spin-lattice interactions in rare earth systems is presented. It is shown that rotational invariance to leading order is ensured only if rotational interactions of first and second order in the displacements are included simultaneously in the spin-lattice Hamiltonian. The rotational second-order interactions yield effects which are as large as those of the linear rotational interaction. It is pointed out that a corresponding statement should hold also for pure strain interactions.The phonon Green's function is calculated for the paramagnetic phase of rare earth systems. It is found that in an applied magnetic field the rotational interactions cause measureable changes of the phonon dispersion and the sound velocity even for cubic symmetry. These effects turn out to be of the same order of magnitude as the conventional field-dependent strain effects and are qualitatively different from the latter. The results of our theory are illustrated by the example of SmSb, and quantitative predictions for the transverse sound velocities are given.