Spin Dynamics of a Canted Antiferromagnet in a Magnetic Field

Abstract

The spin dynamics of a canted antiferromagnet with a quadratic spin-wave dispersion near $\vq =0$ is shown to possess a unique signature. When the anisotropy gap is negligible, the spin-wave stiffness $\dsw (\vq, B) = (ω_{\vq}-B)/q^2$ depends on whether the limit of zero field or zero wavevector is taken first. Consequently, $\dsw $ is a strong function of magnetic field at a fixed wavevector. Even in the presence of a sizeable anisotropy gap, the field dependence of both $\dsw $ and the gap energy distinguishes a canted antiferromagnet from a phase-separated mixture containing both ferromagnetic and antiferromagnetic regions.

10 pages, 3 figures

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Cited by in corpus (1)

• Spin Rotation Technique for Non-Collinear Magnetic Systems: Application to the Generalized Villain Model