SPIN FLUCTUATIONS IN ISOTROPIC FERROMAGNETS NEAR T(C)

被引：4

作者：

BONI, P ^{[1
]}

机构：

[1] PSI,CH-5232 VILLIGEN,SWITZERLAND

来源：

PHYSICA B | 1993年 / 192卷 / 1-2期

关键词：

D O I：

10.1016/0921-4526(93)90111-I

中图分类号：

O469 [凝聚态物理学];

学科分类号：

070205 ;

摘要：

By means of polarized neutrons it is possible to measure different magnetic spin excitation modes in isotropic ferromagnets. The data from EuS shows that the demagnetizing fields have a profound effect on the spin excitations below and above T(C). In particular they prevent the long-wavelength spin fluctuations deltaS parallel-to q from diverging at T(C). This behaviour is reflected in the dynamics of the paramagnetic fluctuations and the spin waves below T(C). The modes with longitudinal polarization are more damped than their transverse counterparts. Above T(C) the relaxation rates follow rather precisely the dipolar dynamic scaling functions calculated recently by mode-coupling theory. Below T(C), the parallel magnetization fluctuations, deltaS parallel-to M, are significantly stronger in EuS than in Ni.

引用

页码：94 / 102

页数：9

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