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arXiv · 1002.2470

Instability of Magnons in Two-dimensional Antiferromagnet at High Magnetic Fields

T. Masuda·S. Kitaoka·S. Takamizawa·N. Metoki·K. Kaneko·K. C. Rule·K. Kiefer·H. Manaka·H. Nojiri
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Abstract

Spin dynamics of the square lattice Heisenberg antiferromagnet, \BaMnGeO, is studied by a combination of bulk measurements, neutron diffraction, and inelastic neutron scattering techniques. Easy plane type antiferromagnetic order is identified at $T \le 4.0$ K. The exchange interactions are estimated as $J_1$ = 27.8(3)${\mu}$eV and $J_2$ = 1.0(1) ${\mu}$eV, and the saturation field $H_{\rm C}$ is 9.75 T. Magnetic excitation measurements with high experimental resolution setup by triple axis neutron spectrometer reveals the instability of one magnon excitation in the field range of $0.7H_{\rm C} \lesssim H \lesssim 0.85H_{\rm C}$.

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T. Masuda, S. Kitaoka, S. Takamizawa, N. Metoki, K. Kaneko, K. C. Rule, K. Kiefer, H. Manaka, H. Nojiri. 2010-02-12. Instability of Magnons in Two-dimensional Antiferromagnet at High Magnetic Fields. https://doi.org/10.1103/physrevb.81.100402

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