Magnon-assisted magnetization reversal of Ni81Fe19 nanostripes on Y3Fe5O12 with different interfaces

Abstract

Magnetic bit writing by short-wave magnons without conversion to the electrical domain is expected to be a game-changer for in-memory computing architectures. Recently, the reversal of nanomagnets by propagating magnons was demonstrated. However, experiments have not yet explored different wavelengths and the nonlinear excitation regime of magnons required for computational tasks. We report on the magnetization reversal of individual 20-nm-thick Ni81Fe19 (Py) nanostripes integrated onto 113-nm-thick yttrium iron garnet (YIG). We suppress direct interlayer exchange coupling by an intermediate layer such as Cu and SiO2. Exciting magnons in YIG with wavelengths λ down to 148 nm we observe the reversal of the integrated ferromagnets in a small opposing field of 14 mT. Magnons with a small wavelength of λ = 195 nm, i.e., twice the width of the Py nanostripes, induced the reversal at an unprecedentedly small spin precessional power of about 1 nW after propagating over 15 μm in YIG. Considerations based on dynamic dipolar coupling explain the observed wavelength dependence of magnon-induced reversal efficiency. For an increased power the stripes reversed in an opposing field of only about 1 mT. Our findings are important for the practical implementation of nonvolatile storage of broadband magnon signals in YIG by means of bistable nanomagnets without the need of an appreciable global magnetic field.