Resonant driving of magnetization precession in a ferromagnetic layer by coherent monochromatic phonons

Abstract

The traditional methods for manipulating the magnetization precession resonantly by microwaves fail to operate at the nanoscale. In the present paper, by using a specially designed ferromagnetic structure, the authors demonstrate resonant driving of the magnetization precession at microwave frequencies by exploiting coherent lattice vibrations. They use a 59-nm ferromagnetic layer as cavity of a phononic Fabry-Perot nanoresonator formed by a semiconductor superlattice. The coherent phonons with resonance frequencies up to 30 GHz are excited by femtosecond laser pulses and feed the magnetization precession within their nanosecond lifetime. The amplitude of the precession increases drastically for resonant conditions when the frequency of the free precession is equal to the frequency of the driving magnetostrictive force.