Figure 5
From: Injection locking of multiple auto-oscillation modes in a tapered nanowire spin Hall oscillator
Spatial distribution of amplitude and linewidth during injection locking. Microwave frequencies of 5.255 GHz (a–c), 5.3 GHz (d–f), 5.35 GHz (g–i), 5.4 GHz (j–l) and 5.625 GHz (k–m) are applied with a nominal ac power of 1 mW and a driving current of Idc = 2.5 mA. (a,d,g,j,m) Spatially resolved BLS measurements. (b,e,h,k,n) local amplitude of the auto-oscillation signal and its FWHM (c,f,i,l,o) as determined from Lorentzian fitting of each spectra. For different frequencies of the injected microwave signal, locking of either only one bullet (SB A for locked bullet A, SB B for locked bullet B) or two spatially separated regions (DBS) is observed. In the locked regions, the linewidth is reduced accompanied by an increase in oscillation amplitude. In addition, the maximum amplitude of the free-running auto-oscillation (green dashed line) and spectral resolution of the BLS microscope (red line) is indicated.
