Laser writing for three-dimensional control of magnetism on a nanometric scale

It is possible to control magnetism in three dimensions, on a nanometric scale, within crystalline films of yttrium iron garnet (YIG). This has been demonstrated by a study conducted by a group of researchers led by the Politecnico di Milano, which has developed an innovative technique based on the use of a focused UV laser to permanently “write” complex magnetic patterns in YIG films.

The study shows how UV laser irradiation induces a stable and localised increase in perpendicular magnetic anisotropy, a fundamental property for the functionality of the material. The modification obtained is confined both laterally and in depth, with a resolution of up to 100 nanometres, without compromising the crystalline structure of the YIG.

The technique also allows the depth of the modification to be precisely modulated by varying the laser power, achieving continuous, three-dimensional control of the magnetic profile.

This approach opens the way to the creation of complex magnetic architectures and grey-scale metamaterials in thin YIG films, with potential applications in magnonic and magneto-optical devices and hybrid platforms for quantum technologies.

The research was conducted by the PhyND group of the Department of Physics at the Politecnico di Milano, in collaboration with the Department of Mechanics and the Department of Energy at the Politecnico di Milano, the University of Perugia, the RPTU Kaiserslautern-Landau University, IFN-CNR and CNR-IOM, with the support of the European Union (Horizon 2020 – B3YOND project), the Ministry of University and Research, the Cariplo Foundation and the CDP Foundation.

The study was published in the journal Nature Communications.