Photoinduced demagnetization and insulator-to-metal transition in ferromagnetic insulating BaFeO$_3$ thin films

TL;DR

This study investigates how laser pulses induce rapid changes in magnetization and electronic states in BaFeO3 thin films, revealing a threshold-driven transition from insulating to metallic states that affects magnetic dynamics.

Contribution

It demonstrates a novel laser-induced transition in BaFeO3 thin films, linking electronic phase change to magnetic demagnetization dynamics with potential for local magnetic control.

Findings

Two types of demagnetization with threshold behavior

Transition from slow to fast demagnetization linked to metallization

Laser excitation induces insulator-to-metal transition

Abstract

We studied the electronic and magnetic dynamics of ferromagnetic insulating BaFeO3 thin films by using pump-probe time-resolved resonant x-ray reflectivity at the Fe 2p edge. By changing the excitation density, we found two distinctly different types of demagnetization with a clear threshold behavior. We assigned the demagnetization change from slow (~ 150 ps) to fast (< 70 ps) to a transition into a metallic state induced by laser excitation. These results provide a novel approach for locally tuning magnetic dynamics. In analogy to heat assisted magnetic recording, metallization can locally tune the susceptibility for magnetic manipulation, allowing to spatially encode magnetic information.