Photo-induced antiferromagnetic-ferromagnetic and spin-state transition in a double-perovskite cobalt oxide thin film

Yujun Zhang,Yasuyuki Hirata,Kohei Yamamoto,Hiroki Wadati,Tsukasa Katayama,Niko Pontius,Christian Schüßler-Langeheine,Keisuke Ikeda,Kohei Yamagami,Akira Chikamatsu,Tetsuya Hasegawa,Kou Takubo

doi:10.1038/s42005-022-00823-4

Abstract

Investigation of ultrafast dynamic behaviors can provide novel insights about the coupling mechanisms among multiple degrees of freedom in condensed matters, such as lattice, magnetism and electronic structure. Here we investigate both the ferromagnetic (FM) and antiferromagnetic (AFM) dynamics of a strongly correlated oxide system, GdBaCo2O5.5 thin film by time-resolved x-ray magnetic circular dichroism in reflectivity (XMCDR) and resonant magnetic x-ray diffraction (RMXD). A photo-induced AFM-FM transition characterized by an increase of the transient XMCDR (sensitive to FM order) beyond the unpumped value and a decay of RMXD (sensitive to AFM order) was observed. The photon-energy dependence of the transient XMCDR and reflectivity could be interpreted as a concomitant photo-induced spin-state transition (SST). The AFM-FM transition and SST couple with each other in the time domain, resulting in unusual dynamic behaviors of the magnetism.

Highlights

Investigation of ultrafast dynamic behaviors can provide novel insights about the coupling mechanisms among multiple degrees of freedom in condensed matters, such as lattice, magnetism and electronic structure
Capturing the element-specific dynamic behaviors of ferromagnetic (FM) order, and antiferromagnetic (AFM) order and complex magnetic structures become possible by employing synchrotron-based resonant magnetic x-ray diffraction (RMXD)[6–8], which cannot be accessed by optical laser probes
To achieve a better understanding about the dynamic behaviors described above, we detailedly investigated the photon energy dependence of the transient x-ray magnetic circular dichroism in reflectivity (XMCDR) and reflectivity

Summary

Introduction

Investigation of ultrafast dynamic behaviors can provide novel insights about the coupling mechanisms among multiple degrees of freedom in condensed matters, such as lattice, magnetism and electronic structure. We investigate both the ferromagnetic (FM) and antiferromagnetic (AFM) dynamics of a strongly correlated oxide system, GdBaCo2O5.5 thin film by time-resolved x-ray magnetic circular dichroism in reflectivity (XMCDR) and resonant magnetic x-ray diffraction (RMXD). Capturing the element-specific dynamic behaviors of ferromagnetic (FM) order, and antiferromagnetic (AFM) order and complex magnetic structures become possible by employing synchrotron-based resonant magnetic x-ray diffraction (RMXD)[6–8], which cannot be accessed by optical laser probes.

Methods

Results

Conclusion