Breaking Space Inversion-Symmetry to Obtain Asymmetric Spin-Wave Excitation in Systems with Nonuniform Magnetic Exchange

Abstract

We report on the consequences of non-uniform exchange in magnetic systems. The quantum mechanical exchange interaction between spins is responsible for the phenomenon of magnetic order, and is generally considered to be uniform across bulk magnetic systems. Partly inspired by the Dzyaloshinskii-Moriya interaction--also known as antisymmetric exchange--we use a linearly varying exchange interaction along a magnetic strip as a route to spatial inversion symmetry-breaking. We find that, in addition to asymmetric modes and localization, spatially-varying exchange can be used to design nonreciprocal magnetic signal excitation at frequencies that are tunable. Moreover, our work predicts nonreciprocity to occur across a vast range of frequencies up to hundreds of GHz. Such spin wave engineering is a key area of ongoing research in the fields of magnonics and spintronics, which are expected to enable the next generation of communication technology. Analogous nonreciprocity is expected to occur in other wave systems with gradient properties.

References in corpus (6)

• Nonreciprocal Transmission of Microwave Acoustic Waves in Nonlinear Parity-Time Symmetric Resonators
• Chiral spin-wave velocities induced by all-garnet interfacial Dzyaloshinskii-Moriya interaction in ultrathin yttrium iron garnet films
• Experimental Observation of Nonreciprocal Waves in a Resonant Metamaterial Beam
• Interface boundary conditions for dynamic magnetization and spin wave dynamics in a ferromagnetic layer with the interface Dzyaloshinskii-Moriya interaction
• Determination of exchange constants of Heusler compounds by Brillouin light scattering spectroscopy: application to Co${}_2$MnSi
• Asymmetric spin wave dispersion due to a saturation magnetization gradient

Cited by in corpus (2)

• All-magnonic Stern-Gerlach effect in antiferromagnets
• Nonreciprocal Spin Waves Driven by Left-Hand Microwaves