Time-spliced X-ray Diffraction Imaging

TL;DR

This paper demonstrates a novel method for one-dimensional coherent diffraction imaging by splicing images from different delays, enabling the study of ultrafast magnetic dynamics in complex oxides with atomic resolution.

Contribution

It introduces a time-splicing technique for X-ray diffraction imaging to analyze one-dimensional non-equilibrium dynamics at atomic resolution.

Findings

Imaged the evolution of antiferromagnetic order in a complex oxide heterostructure.

Observed a magnetic front propagating faster than the speed of sound after mid-infrared excitation.

Showed the feasibility of applying diffraction imaging to confined one-dimensional objects.

Abstract

Diffraction imaging of non-equilibrium dynamics at atomic resolution is becoming possible with X-ray free-electron lasers. However, there are unresolved problems with applying this method to objects that are confined in only one dimension. Here I show that one-dimensional coherent diffraction imaging is possible by splicing together images recovered from different delays in a time-resolved experiment. This is used to image the time and space evolution of antiferromagnetic order in a complex oxide heterostructure from measurements of a resonant soft X-ray diffraction peak. Mid-infrared excitation of the substrate is shown to lead to a magnetic front that propagates at a velocity exceeding the speed of sound, a critical observation for the understanding of driven phase transitions in complex condensed matter.