Time-resolved imaging of three-dimensional nanoscale magnetization dynamics

Understanding and control of the dynamic response of magnetic materials with a three-dimensional magnetization distribution is important both fundamentally and for technological applications. From a fundamental point of view, the internal magnetic structure and dynamics in bulk materials still need to be mapped 1 , including the dynamic properties of topological structures such as vortices 2 , magnetic singularities 3 or skyrmion lattices 4 . From a technological point of view, the response of inductive materials to magnetic fields and spin-polarized currents is essential for magnetic sensors and data storage devices 5 . Here, we demonstrate time-resolved magnetic laminography, a pump–probe technique, which offers access to the temporal evolution of a three-dimensional magnetic microdisc with nanoscale resolution, and with a synchrotron-limited temporal resolution of 70 ps. We image the dynamic response to a 500 MHz magnetic field of the complex three-dimensional magnetization in a two-phase bulk magnet with a lateral spatial resolution of 50 nm. This is achieved with a stroboscopic measurement consisting of eight time steps evenly spaced over 2 ns. These measurements map the spatial transition between domain wall motion and the dynamics of a uniform magnetic domain that is attributed to variations in the magnetization state across the phase boundary. Our technique, which probes three-dimensional magnetic structures with temporal resolution, enables the experimental investigation of functionalities arising from dynamic phenomena in bulk and three-dimensional patterned nanomagnets 6 . Knowledge and control of the dynamic response in micromagnetic configurations is important both for understanding their fundamental properties and for their use in technological applications. Pump–probe magnetic laminography now unveils the evolution of the magnetization in a three-dimensional system with nanoscale resolution.