Figure 3
From: Injection locking of multiple auto-oscillation modes in a tapered nanowire spin Hall oscillator
Auto-oscillatory modes. (a) Measured BLS intensity (black dots) integrated over four equidistant x-positions and inverse intensity (blue triangles). The output power calculated according to an analytical approximation15 (solid and dashed lines) agrees well with the experimental data when assuming a critical current ζ = 2.28 mA, nonlinear coefficient Q = 0.8 and noise η = 1. (b) BLS spectra recorded for Idc = 2.5 mA along the SHO with the intensity color coded on a logarithmic scale. Two regions of pronounced intensity and different frequency are observed at x = 480 nm and x = 1250 nm. (c) Two exemplary BLS spectra measured at different positions for Idc = 2.5 mA. A low-frequency (LF), middle-frequency (MF) and high-frequency (HF) peak can be distinguished and fitted by Lorentzian functions. (d,e) Amplitude distribution and local frequency of the LF, MF, and HF peak along the SHO (x-axis). The black line in (d) shows the amplitude distribution of the auto-oscillating mode according to the proposed formation of two spin-wave bullets25.
