Implementing sub-ns time resolution into magnetic x-ray microscopies

Abstract

X-ray microscopies using polarized x-rays allow for imaging magnetic microstructures down to a 20 nm lateral resolution with chemical sensitivity. Utilizing the pulsed time structure of synchrotron radiation a sub-ns time resolution can be implemented by performing stroboscopic pump-and-probe experiments. The temporal evolution of the magnetization in a 50 nm thin circular permalloy element with a diameter of 2 μm could be imaged with magnetic transmission x-ray microscopy. The magnetic pump pulse to the sample was generated electronically with a rise time of less than 100 ps up to 150 Oe by a microcoil. The probe pulse is the flash of the circularly polarized x-ray beam with a pulse width of about 70 ps at a frequency of 3 MHz. Images were recorded at varying delay times between pump and probe pulse up to 2000 ps. Fast detection schemes utilizing avalanche photo diodes are capable to pick individual bunches from the storage ring.