Magneto-Optical Properties of Thin Films

Magneto-optical phenomena in thin films arise from the interaction between confined magnetic order and incident light, producing measurable changes in intensity, polarization and phase upon reflection or transmission. Key effects include the Kerr and Faraday responses, which are sensitive to surface and interface magnetisation in layers often only a few nanometres thick. Control of magnetic anisotropy, spin dynamics and orbital magnetism at these dimensions underpins applications in high-density data storage, magnetic sensing and emerging spintronic devices. Progress in deposition techniques and advanced characterisation has enabled precise tuning of chemical composition, interfacial engineering and strain, thereby refining optical contrast and magnetic switching thresholds. Studies increasingly focus on real-time imaging of domain evolution, current-induced torques and the integration of magneto-optical layers with plasmonic and photonic structures to amplify signal levels and facilitate device miniaturisation.

Research from Nature Portfolio

Recent studies have introduced an approach to quantify spin–orbit torque directly from single magnetic images by counterbalancing radial current-induced fields with an external magnetic bias. This technique utilises concentric electrodes to stabilise circular magnetisation states, enabling measurement of torque magnitudes without complex microfabrication. Another innovation employs extreme anti-reflection coatings to enhance Kerr microscopy on ultrathin cobalt films. By minimising background reflection, Kerr amplitudes exceeding 20° and sub-wavelength domain imaging have been realised at room temperature, offering a low-cost optical route to real-time monitoring of nanoscale spin textures. Together these advances strengthen the toolkit for non-invasive, high-sensitivity exploration of thin-film magnetism and spin dynamics.

Magneto-Optical Properties of Thin Films publication trend

The graph below shows the total number of articles in magneto-optical properties of thin films across all publications each year (not limited to Nature Index journals).

Technical terms

Magneto-optical Kerr effect (MOKE): change in polarization and intensity of light reflected from a magnetised surface, used to probe surface magnetisation dynamics.

Spin–orbit torque: torque exerted on magnetic moments by spin currents generated via spin–orbit coupling under applied electric currents.

Magnetic anisotropy: variation of magnetic energy with the orientation of magnetisation in a material, determining preferred magnetic axes.

Dielectric tensor: anisotropic permittivity matrix describing the dependence of a material’s optical response on direction and polarization of the electromagnetic field.

References

1. Tailoring Magnetic Anisotropy in Ultrathin Cobalt by Surface Carbon Chemistry. Advanced Electronic Materials (2024).
2. Measurement of spin–orbit torque using field counterbalancing in radial current geometry. Scientific Reports (2023).
3. Extreme anti-reflection enhanced magneto-optic Kerr effect microscopy. Nature Communications (2020).
4. The 2022 magneto-optics roadmap. Journal of Physics D (2022).
5. Spectroscopic ellipsometry and magneto-optical Kerr effect spectroscopy study of thermally treated Co60Fe20B20 thin films. Journal of Physics Condensed Matter (2019).