Phase Mixing in Ultrafast Transient Grating Study of Eu₂Ir₂O₇ Thin Film

Ultrafast pump-probe experiment offers a pathway to study the non-equilibrium dynamics of a wide range of materials. Here, we present the result of a comprehensive time-resolved study on the transient magnetic order formation of Eu₂Ir₂O₇. Eu₂Ir₂O₇ is a member of the rare earth pyrochlore iridate family with all-in-all-out antiferromagnetic order below T_N=110K. We employed various ultrafast techniques using an optical probe, a THz probe, and transient grating pump-probe with photoexcitation at 1.55eV, corresponding to the transition energy between the J_eff=3/2 isospin state and the upper Hubbard band. We focus on the heterodyning transient grating results here, which show a unique phase mixing behavior with a strong correlation to magnetic orderings. With this and consequent studies, we aim to understand the nature of the interaction between this exchange and the magnetic properties of the pyrochlore iridate Eu₂Ir₂O₇.