Pyroelectricity and field-induced spin-flop in (4-(Aminomethyl)pyridinium)2 MnCl4 · 2H2O

Large single crystals of (4-(Aminomethyl)pyridinium)2 MnCl4 · 2H2O (1) were grown by slow evaporation of solution. The crystal structure was solved to be Pī, which belongs to the central symmetric space group. But small pyroelectric current was detected, as well as a ferroelectric hysteresis loop. The pyroelectric and the ferroelectric properties were attributed to the strain caused by defects. Temperature-dependent magnetic curves and the M-H curve show that 1 is antiferromagnetic ordering below 2.5 K. A field-induced spin-flop is observed in the antiferromagnetic ordering state.