Imaging of magnetization and its dynamics on the micro- and nanoscale by Scanning Transmission X-ray Microscopy*

Magnetic materials on the micro- and nanoscale are addressing a wide spectrum of contemporary challenges ranging from cancer research towards spintronic and magnonic solutions for modern information technology. The synchrotron-based technique of Scanning Transmission X-ray Microscopy (STXM) allows the element-specific and spatially resolved (≥ 10 nm [1]) chemical and magnetic characterization of such materials in a wide range of X-ray absorption energies. By exploiting X‐ray Magnetic Circular Dichroism (XMCD), information on orientation and size of magnetic moments can be determined, probing the sample by circularly polarized X-rays at a photon energy set to an X-ray absorption edge of the investigated element. Time-resolved STXM (TR-STXM) allows to monitor dynamic excitations of the magnetization up to 10 GHz with  < 30 ps sampling [2]. The talk will introduce Scanning Transmission X-Ray Microscopy, with the focus on time-resolved STXM and its application to element-specifically detect magnetization dynamics on the micro- and nanometer scale. TR-STXM imaging of uniform and non-uniform resonant responses in Py/Co bilayer, and Py stripe microstructures [3] and the resonant response of Fe₃O₄ nanoparticle chains within magnetotactic bacteria Magnetospirillum Magnetotacticum [4] are shown.

  

1.         W. Chao, P. Fischer, et al. Opt. Express, 2012. 20(9): p. 9777-9783.

2.         S. Bonetti, R. Kukreja, et al. Rev. Sci. Instrum., 2015. 86(9): p. 093703-1-093703-9.

3.         S. Pile, T. Feggeler, et al. Appl. Phys. Lett., 2020. 116(7): p. 072401-1-072401-5.

4.         T. Feggeler, R. Meckenstock, et al. Phys. Rev. Res., 2021. 3(3).