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arXiv · 1105.1893

Spontaneous magnon decays in planar ferromagnet

V. A. Stephanovich·M. E. Zhitomirsky
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Abstract

We predict that spin-waves in an easy-plane ferromagnet have a finite lifetime at zero temperature due to spontaneous decays. In zero field the damping is determined by three-magnon decay processes, whereas decays in the two-particle channel dominate in a transverse magnetic field. Explicit calculations of the magnon damping are performed in the framework of the spin-wave theory for the $XXZ$ square-lattice ferromagnet with an anisotropy parameter $λ<1$. In zero magnetic field the decays occur for $λ^*<λ<1$ with $λ^*\approx 1/7$. We also discuss possibility of experimental observation of the predicted effect in a number of ferromagnetic insulators.

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V. A. Stephanovich, M. E. Zhitomirsky. 2011-05-10. Spontaneous magnon decays in planar ferromagnet. https://doi.org/10.1209/0295-5075%2F95%2F17007

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