Three-dimensional nanoscale control of magnetism in crystalline Yttrium Iron Garnet

TL;DR

This paper demonstrates a novel laser-based method to precisely control three-dimensional magnetic properties in crystalline YIG films, enabling advanced magnonic and magneto-optic device functionalities.

Contribution

It introduces a non-destructive, laser-driven technique for 3D nanoscale magnetic modulation in crystalline YIG, surpassing previous 2D limitations.

Findings

Achieved stable, giant enhancement of perpendicular magnetic anisotropy

Enabled continuous depth-control of magnetic modulation

Demonstrated tunable spin-wave band structure and non-reciprocity

Abstract

The exceptional magnetic, optical and phononic properties of Yttrium Iron Garnet (YIG) make it unique for spin-wave based and photonic applications. Yet, nanostructuring crystalline YIG and manipulating its magnetism in a non-destructive way is an outstanding challenge, and so far mostly limited to two-dimensional capabilities. Here, we show that irradiation of single-crystal YIG films with a focused UV laser drives a stable, giant enhancement of the perpendicular magnetic anisotropy, preserving the crystalline quality. This modulation is highly confined at the nanoscale in both the lateral and vertical directions, and its extension within the volume can be finely tuned with a continuous depth-control. By harnessing these three-dimensional anisotropy profiles, we demonstrate a large tuning of the spin-wave band structure, volume spatial localization, and non-reciprocity, realizing proof-of-principle 3D magnonic crystals. This straightforward, single-step, laser nanofabrication of three-dimensional magnetic systems based on crystalline YIG thin films opens the way to design novel functions in magnonic and magneto-optic devices.