An A‐Site Mixed‐Ammonium Solid Solution Perovskite Series of [(NH2NH3)x(CH3NH3)1−x][Mn(HCOO)3] (x=1.00–0.67)

The A-site mixed-ammonium solid solutions of metal-organic perovskites [(NH2 NH3 )x (CH3 NH3 )1-x ][Mn(HCOO)3 ] (x=1.00-0.67) exhibit para- to ferroelectric diffuse phase transitions with lowered transition temperatures from x=1.00 to 0.67. These properties are due to the decreased framework distortion and polarization in their low temperature ferroelectric phases caused by the increased CH3 NH3 (+) concentration.