Glass-like recovery of antiferromagnetic spin ordering and dimensional crossover in a photo-excited manganite Pr$_{0.7}$Ca$_{0.3}$MnO$_3$

TL;DR

This study investigates the ultrafast dynamics of antiferromagnetic spin ordering in a manganite, revealing a glass-like recovery and a dimensional crossover influenced by photo-excitation, which impacts the material's electronic phase transitions.

Contribution

It demonstrates the first observation of a glass-like recovery of spin order and a dimensional crossover in a photo-excited manganite using time-resolved resonant soft x-ray scattering.

Findings

Glass-like recovery of spin ordering observed.

Dimensional crossover from quasi-1D to 3D with increasing fluence.

Collapse of spin order correlates with insulator-metal transition.

Abstract

Electronic orderings of charges, orbitals and spins are observed in many strongly correlated electron materials, and revealing their dynamics is a critical step toward understanding the underlying physics of important emergent phenomena. Here we use time-resolved resonant soft x-ray scattering spectroscopy to probe the dynamics of antiferromagnetic spin ordering in the manganite Pr$_{0.7}$Ca$_{0.3}$MnO$_3$ following ultrafast photo-exitation. Our studies reveal a glass-like recovery of the spin ordering and a crossover in the dimensionality of the restoring interaction from quasi-1D at low pump fluence to 3D at high pump fluence. This behavior arises from the metastable state created by photo-excitation, a state characterized by spin disordered metallic droplets within the larger charge- and spin-ordered insulating domains. Comparison with time-resolved resistivity measurements suggests that the collapse of spin ordering is correlated with the insulator-to-metal transition, but the recovery of the insulating phase does not depend on the re-establishment of the spin ordering.