Ultrasonic Attenuation in Magnetics at Low Temperatures

概要

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The attenuation of the longitudinal sound in ferro- and antiferromagnetic systems at low temperatures where the systems are well described by spin waves is studied theoretically. As an interaction of the sound with the spin system the modulation of the Heisenberg exchange interaction due to the lattice vibrations is adopted. The dependence of the attenuation constant on temperature and the wave number of the sound is determined for both ferro- and antiferromagnets with uniaxial anisotropy. In ferromagnets, the results obtained agree with those of Kaganov and Chikavashvili at very low temperatures. The attenuation is also studied for higher temperatures where the damping effect of the spin waves becomes appreciable. In antiferromagnets the attenuation constant has various expressions depending on the relative magnitudes of temperature, the wave number, the exchange interaction and the anisotropy constant.
理論物理学刊行会の論文
1969-04-25