Torque acting on the magnetization vector during 90$^\circ$ pulsed magnetization of real garnet ferrite films with in-plane anisotropy

The torque acting on the magnetization vector in the course of 90$^\circ$ pulsed magnetization of real garnet ferrite films with in-plane and biaxial anisotropy is calculated by a method in which the operating point trajectory is analyzed. The position of the operating point is described by azimuthal angle $\varphi$ and torque component $T_m$ produced by pulsed magnetizing field $H_m$. The time dependence of resultant torque $T_{\varphi}$ has a sharply ascending portion, within which the nonlinear magnetization oscillations are excited. Additionally, the shape of the curve $T_\varphi(t)$ within this portion depends on pulse rise time $\tau_f$ only slightly. These results explain the weak dependence of the magnetization oscillation strength on $\tau_f$, which was experimentally found previously. It is shown analytically that when $\tau_f$ decreases to 2.5–3.0 ns within the initial portion of the curve $T_{\varphi}(t)$ at $\varphi\le$ 10$^\circ$, there arises an extra maximum of torque $T_{\varphi}$. Simultaneously, an additional voltage peak appears in the initial part of the longitudinal magnetization signal. The appearance of the additional voltage peak is confirmed experimentally.