3 research outputs found
Electrical detection of parallel parametric amplification and attenuation in / bilayer disk
We report a systematic quantitative evaluation of parametric amplification
gain of magnetization dynamics in ytirrium iron garnet
() thin disk via a.c. spin pumping
and inverse spin Hall effect. We demonstrate its signature phase-dependence
where amplification and attenuation occur every phase shift of
the input signal. The results also show the pump-power dependence of the gain
that is explained well by our theoretical model. Finally, the optimal
conditions for the amplification is investigated by measuring the magnetic
field dependence, where we find the highest gain of 11.4 dB.Comment: 6 pages, 3 figures, 14 panel
Switching of magnon parametric oscillation by magnetic field direction
Parametric oscillation occurs when the resonance frequency of an oscillator
is periodically modulated. Owing to time-reversal symmetry breaking in magnets,
nonreciprocal magnons can be parametrically excited when spatial-inversion
symmetry breaking is provided. This means that magnons with opposite
propagation directions have different amplitudes. Here we demonstrate switching
on and off the magnon parametric oscillation by reversing the external field
direction applied to a YFeO micro-structured film. The result
originates from the nonreciprocity of surface mode magnons, leading to
field-direction dependence of the magnon accumulation under a nonuniform
microwave pumping. Our numerical calculation well reproduces the experimental
result.Comment: 5 pages, 4 figure