Voltage-Controlled Reconfigurable Magnonic Crystal at the Submicron Scale

TL;DR

This paper demonstrates a voltage-controlled, reconfigurable magnonic crystal at the submicron scale by combining multiferroic and ferromagnetic materials, enabling dynamic control of spin wave propagation and bandgap formation.

Contribution

It introduces a novel epitaxial heterostructure of multiferroics and ferromagnets for voltage-controlled magnonic reconfigurability at the nanoscale.

Findings

Achieved a remnant electrical polarization in BiFeO3 with 500 nm periodicity.

Demonstrated a magnonic bandgap with over 20 dB rejection.

Showed effective modulation of spin wave spectra via voltage control.

Abstract

Multiferroics offer an elegant means to implement voltage-control and on the fly reconfigurability in microscopic, nanoscaled systems based on ferromagnetic materials. These properties are particularly interesting for the field of magnonics, where spin waves are used to perform advanced logical or analogue functions. Recently, the emergence of nano-magnonics {\color{black} is expected to} eventually lead to the large-scale integration of magnonic devices. However, a compact voltage-controlled, on demand reconfigurable magnonic system has yet to be shown. Here, we introduce the combination of multiferroics with ferromagnets in a fully epitaxial heterostructure to achieve such voltage-controlled and reconfigurable magnonic systems. Imprinting a remnant electrical polarization in thin multiferroic $\mathrm{BiFeO_3}$ with a periodicity of $500\,\mathrm{nm}$ yields a modulation of the effective magnetic field in the micron-scale, ferromagnetic $\mathrm{La_{2/3}Sr_{1/3}MnO_3}$ magnonic waveguide. We evidence the magneto-electrical coupling by characterizing the spin wave propagation spectrum in this artificial, voltage induced, magnonic crystal and demonstrate the occurrence of a robust magnonic bandgap with $>20 \,\mathrm{dB}$ rejection.