Strain-affected ferroelastic domain walls in RbMnFe charge-transfer materials undergoing collective Jahn-Teller distortion.

Many rubidium manganese hexacyanoferrate materials, with the general formula Rb Mn[Fe(CN)]·HO, exhibit diverse charge-transfer-based functionalities due to the bistability between a high temperature Mn( = 5/2)Fe( = 1/2) cubic phase and a low-temperature Mn( = 2)Fe( = 0) tetragonal phase. The collective Jahn-Teller distortion on the Mn sites is responsible for the cubic-to-tetragonal ferroelastic phase transition, which is associated with the appearance of ferroelastic domains. In this study, we use X-ray diffraction to reveal the coexistence of 3 types of ferroelastic tetragonal domains and estimate the spatial extension of the strain around the domain walls, which represents about 30% of the volume of the crystal.

Ultrafast and persistent photoinduced phase transition at room temperature monitored by streaming powder diffraction.

Ultrafast photoinduced phase transitions at room temperature, driven by a single laser shot and persisting long after stimuli, represent emerging routes for ultrafast control over materials' properties. Time-resolved studies provide fundamental mechanistic insight into far-from-equilibrium electronic and structural dynamics. Here we study the photoinduced phase transformation of the RbMnCo[Fe(CN)] material, designed to exhibit a 75 K wide thermal hysteresis around room temperature between MnFe tetragonal and MnFe cubic phases.