Phase transitions in (CnH2n 1NH2)3Mnc14

Abstract

(CnH2n+1NH3)2MnCl4 compounds consist of perovskite type layers sandwiched between hydrocarbon radical layers and can be regarded as two-dimensional perovskites. New phase transitions were detected in compounds with n ≥ 3. All compounds show at room temperature an orthorhombic modification with twinning similar to domain patterns in BaTiO3. At higher temperatures the walls disappear at a second order transition. No evidence of ferroelectricity could be found for the room temperature phase of the n = 1 compound. The transitions are shifted by deuteration and a change in the chain length of the alky1 changes also the phase sequence.