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

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 $H_{\mathrm{C}}$ 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 $0.7H_{\mathrm{C}}\lesssim H\lesssim 0.85H_{\mathrm{C}}$.

5 pgase, 5 figuers, to be published in PRB RC

References in corpus (4)

• Spin-waves in triangular lattice antiferromagnet: decays, spectrum renormalization, and singularities
• The antiferromagnetic spin-1/2 Heisenberg model on the square lattice in a magnetic field
• Numerical evidence for unstable magnons at high fields in the Heisenberg antiferromagnet on the square lattice
• Collective excitations in two-dimensional antiferromagnet in strong magnetic field

Cited by in corpus (24)

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• Microwave non-reciprocity of magnon excitations in a non-centrosymmetric antiferromagnet Ba${}_2$MnGe${}_2$O${}_7$
• Discovering momentum-dependent magnon spin texture in insulating antiferromagnets: Role of the Kitaev interaction
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• Magnetization Plateaus in the Two-dimensional S = 1/2 Heisenberg Model with a 3$\times$3 Checkerboard Structure
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