Revealing 3D magnetization of thin films with soft X-ray tomography: magnetic singularities and topological charges

• Published in: Nature communications Vol. 11; no. 1; p. 6382
• Main Authors: Hierro-Rodriguez, A., Quirós, C., Sorrentino, A., Alvarez-Prado, L. M., Martín, J. I., Alameda, J. M., McVitie, S., Pereiro, E., Vélez, M., Ferrer, S.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 14-12-2020; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301; 639/301/119; 639/301/357; 639/301/930; 639/925; Dichroism; Experimental methods; Ferromagnetic materials; Heterostructures; Humanities and Social Sciences; Magnetic dichroism; Magnetism; Magnetization; multidisciplinary; Science; Science (multidisciplinary); Singularities; Soft x rays; Spatial discrimination; Spatial resolution; Thin films; Tomography; Topology
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-20119-x

The knowledge of how magnetization looks inside a ferromagnet is often hindered by the limitations of the available experimental methods which are sensitive only to the surface regions or limited in spatial resolution. Here we report a vector tomographic reconstruction based on soft X-ray transmission microscopy and magnetic dichroism data, which has allowed visualizing the three-dimensional magnetization in a ferromagnetic thin film heterostructure. Different non-trivial topological textures have been resolved and the determination of their topological charge has allowed us to identify a Bloch point and a meron-like texture. Our method relies only on experimental data and might be of wide application and interest in 3D nanomagnetism.
Although magnetic tomography has been used in the past to determine the 3D magnetization of materials its application to thin films remains challenging. Here the authors reconstruct the magnetization of a thin film, enabling the measurement of topological charges of magnetic singularities.