Excitation of Spin Waves in an In-Plane-Magnetized Ferromagnetic Nanowire Using Voltage-Controlled Magnetic Anisotropy

It is demonstrated by analytical calculations and micromagnetic simulations that a microwave pumping by means of a voltage-controlled magnetic anisotropy (VCMA) could excite propagating spin waves in a ferromagnetic nanowire with in-plane static magnetization, and only the parametric excitation is possible. The efficiency of the parametric excitation is proportional to the out-of-plane component of the dynamic magnetization, and it is nonvanishing in the entire range of spin-wave wave vectors. This property ensures the excitation of spin waves in a wide frequency range (up to tens of gigahertz) using practically achievable amplitudes of the VCMA pumping. For a Fe/MgO nanowire, the threshold of parametric excitation of spin waves lies in the range 0.5-1 V/nm and only weakly depends on the nanowire width.