Abstract
Many rubidium manganese hexacyanoferrate materials, with the general formula Rb (x) Mn[Fe(CN)(6)]((x+2)/3)·zH(2)O, exhibit diverse charge-transfer-based functionalities due to the bistability between a high temperature Mn(II)(S = 5/2)Fe(III)(S = 1/2) cubic phase and a low-temperature Mn(III)(S = 2)Fe(II)(S = 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.