Extended Data Fig. 4: Schematics of magnetization dynamics under parametric pumping.
a,b, Schematics of magnetization precession component and AC magnetic field when phase-matching conditions are satisfied. c, Snapshots of the elliptical magnetization (M) precession under an ac magnetic field (bac, pink arrows) and its torque (light blue arrows) that enforce or suppress the torques by the dc magnetic field \(-\gamma {\bf{M}}\times {\bf{B}}\) (black arrows). d, Top view of magnetization precession without AC magnetic field. e, Top view of magnetization precession under parametric pumping as in c. The torque arrow due to AC magnetic field (light blue) directs the same direction as \({\dot{M}}_{Y}\) when \({M}_{Y}\) takes maximum or minimum, while it directs the opposite when \({M}_{Y}=0\), leading to smaller noise along\({M}_{Y}\) and larger noise in \({M}_{X}\).
