Engineering Magnetic Anisotropy in Permalloy Films via Atomic Force Nanolithography

TL;DR

This paper demonstrates how atomic force nanolithography can precisely engineer magnetic anisotropy in permalloy films by patterning nanoscale grooves, enabling tunable magnetic properties and domain control for advanced applications.

Contribution

It introduces a versatile nanolithography method to controllably induce and tune magnetic anisotropy in ferromagnetic thin films at the microscale.

Findings

Nanoscale groove arrays induce in-plane uniaxial anisotropy.

Anisotropy increases with decreasing groove period and deeper engraving.

Patterned microstructures direct domain configurations and domain-wall paths.

Abstract

Atomic force nanolithography provides a precise method for sculpting magnetic thin films, enabling controlled engineering of magnetic anisotropy in soft ferromagnets at the microscale. We demonstrate that nanoscale groove arrays patterned into permalloy (Ni80Fe20) films induce a robust in-plane uniaxial anisotropy, with the easy axis aligned along the groove direction. The anisotropy field is shown to increase with decreasing groove period and increasing engraving depth, offering continuous tunability of magnetic hardness within a single fabrication step. Artificially engraved microstructures further allow domain configurations and domain-wall trajectories to be directed along predefined pathways, exemplified by the creation of a chessboard-like magnetic landscape. Owing to its adaptability to diverse ferromagnetic materials and arbitrary corrugation geometries, this approach provides a versatile platform for tailoring in-plane magnetic anisotropy. Concrete applications are demonstrated in the design of magnonic elements and anisotropic magnetoresistance sensors.