Field-dependence of magnon decay in yttrium iron garnet thin films

Abstract

We discuss threshold field-dependence of the decay rate of the uniform magnon mode in yttrium iron garnet (YIG) thin films. We demonstrate that decays must cease to exist in YIG films of thickness less than 1 μm, the lengthscale defined by the exchange length. We show that due to the symmetry of the three-magnon coupling the decay rate is linear in ΔH=(Hc-H) in the vicinity of the threshold field Hc instead of the step-like ΓΘ(ΔH) expected from the two-dimensional character of magnon excitations in such films. For thicker films, the decay rate should exhibit multiple steps due to thresholds for decays into a sequence of the two-dimensional magnon bands. For yet thicker films, such thresholds merge and crossover to the three-dimensional single-mode behavior: Γ|ΔH|^{3/2}.

4+ pages, 1+ page of supplemental material, 5 figures, PRB Rapid Communications, published version

References in corpus (4)

• Stability of Bose Einstein condensates of hot magnons in YIG
• Microscopic spin-wave theory for yttrium-iron garnet films
• Bose-Einstein condensation at finite momentum and magnon condensation in thin film ferromagnets
• Anomalously large damping of long-wavelength quasiparticles caused by long-range interaction

Cited by in corpus (5)

• Spontaneous Magnon Decays
• Magnon damping in the zigzag phase of the Kitaev-Heisenberg-$\Gamma$ model on a honeycomb lattice
• Thermalization of magnons in yttrium-iron garnet: nonequilibrium functional renormalization group approach
• Effect of magnon decays on parametrically pumped magnons
• Role of dimensionality in spontaneous magnon decay: easy-plane ferromagnet