Local magnetic anisotropy controlled by a surface nano-modulation

TL;DR

This paper demonstrates how surface nano-modulation of substrates can control magnetic anisotropy in thin films, enabling precise local magnetic property tuning for advanced sensor applications.

Contribution

It introduces a method to manipulate magnetic anisotropy in NiFe films via topological surface modulation, overcoming intrinsic anisotropy and creating orthogonal easy axes.

Findings

Patterned substrates can override intrinsic anisotropy.

Multiple easy axes can be defined on a single substrate.

Control over anisotropy enhances magnetic sensor design.

Abstract

A topological modulation of magnetic thin films can induce a magnetic anisotropy of magnetostatic origin. In this letter, we report on the magnetic properties of NiFe layers deposited on wavy shaped Si substrates. Without any modulation, our films always present an intrinsic anisotropy. We show unambiguously that patterning the substrate can overcome this anisotropy and even impose a different easy axis of magnetization. This allows the definition of two orthogonal easy axes at different places on the same substrate. This control of anisotropy both in direction and intensity paves the way to the realization of high precision bidimensional magnetic sensors.