Spin torque driven mode hybridization and band engineering in nanopatterned magnonic crystals

TL;DR

This paper demonstrates dynamic control of spin-wave dispersion and hybridization in a nanopatterned magnonic crystal using inhomogeneous spin torque, enabling reconfigurable magnonic states for spintronic devices.

Contribution

It introduces a method to electrically tune magnonic band structures and mode hybridization in a bicomponent nanopatterned crystal via spin torque modulation.

Findings

Observed avoided crossing between localised and propagating modes

Achieved tunable hybridisation gaps and band deformation

Enabled controlled mode conversion and reconfigurable states

Abstract

Spin wave propagation and dynamic control are essential for reconfigurable magnonic and spintronic devices. Here, tunable mode coupling and band hybridisation are demonstrated in a nanopatterned bicomponent magnonic crystal consisting of a Permalloy/heavy metal bilayer patterned with a two dimensional array of Co nanodots. Using the plane wave method and the linearised Landau Lifshitz equation with a field like torque term, we show that inhomogeneous current induced spin torque produces periodic modulation of the magnonic frequency, enabling dynamic control of spin-wave dispersion. A pronounced avoided crossing between localised and propagating Damon Eshbach modes is observed, leading to tunable hybridisation gaps, band deformation, and enhanced mode mixing. The spin torque induced modulation enables controlled mode conversion and reconfigurable hybrid magnonic states, demonstrating efficient electrical tuning of nanoscale spin-wave dynamics.