Coupling between ferroelasticity and magnetization in two-dimensional organic–inorganic perovskites (C6H5C2H4NH3)2MCl4 (M = Mn, Cu, Fe)†

Materials with coexistence of two or more ferroic orders are known as multiferroics. Magneto-elastic multiferroics, where ferromagnetism and ferroelasticity coexist, have been rarely reported previously. We studied the magneto-elastic multiferroic properties of two-dimensional organic–inorganic perovskites having the formulas (PEA)₂MnCl₄, (PEA)₂CuCl₄ and (PEA)₂FeCl₄ (PEA = C₆H₅C₂H₄NH₃). All three exhibited ferroelasticity but the manganese and iron compounds showed canted antiferromagnetism and the copper one showed ferromagnetism. Also, only (PEA)₂FeCl₄ displayed a shift of magnetization when the sample was cooled in a magnetic field from above the magnetic ordering temperature. We propose that the magnetization shift originates from the coupling between ferroelasticity and magnetization via spin–orbit coupling (SOC). This work would shed light on understanding the coupling mechanism between ferroelasticity and magnetization towards the interesting role of SOC in ferroelastic materials.