Extended Depth of Field Magneto-Optical Kerr Microscopy for Applications in 3D Nanomagnetism

TL;DR

This paper introduces an extended depth of field magneto-optical Kerr microscopy technique that enables high-resolution 3D imaging of magnetic nanostructures on curved or tilted surfaces, overcoming traditional shallow depth of field limitations.

Contribution

The authors develop a novel imaging approach combining through-focus scanning and image stitching to achieve sharp 3D magnetic domain images on non-planar samples.

Findings

Successfully images non-planar magnetic samples with high resolution.

Enables quantitative analysis of magnetic domain morphology.

Provides a practical, versatile tool for 3D magnetic imaging.

Abstract

High-resolution imaging of magnetic nanostructures is essential for understanding fundamental spin phenomena and designing advanced devices. Recent developments in three-dimensional (3D) nanomagnetism have highlighted the growing need for imaging techniques that can capture magnetic structures across curved or tilted surfaces with high sensitivity. Though widely used as a powerful technique for imaging magnetization states, conventional magneto-optical Kerr effect (MOKE) microscopy faces inherent limitations in measuring non-planar systems due to its shallow depth of field (DOF). Here, we present an extended depth of field MOKE imaging approach, combining through-focus scanning with image-stitching-based reconstruction, to obtain sharp and well-resolved magnetic domain images across non-planar sample geometries. The method is validated on both perpendicularly and in-plane magnetized films tilted on purpose for this study, enabling quantitative analysis of domain morphology and detection sensitivity. This laboratory-accessible technique provides a fast and versatile route for 3D magnetic imaging, complementing large-scale X-ray-based methods and offering a practical tool for investigating non-planar magnetic samples with tilted or curved 3D geometries.