Above-Room-Temperature Magnetodielectric Coupling in a Possible Molecule-Based Multiferroic: Triethylmethylammonium Tetrabromoferrate(III)

A possible above-room-temperature molecular multiferroic, triethylmethylammonium tetrabromoferrate(III) (1), has been discovered. Its ferroelectric and magnetic phase transitions take place at almost the same temperature (similar to 360 K), resulting in strong magnetodielectric (MD) coupling, with a MD ratio of 18% at 0.6 MHz. Interestingly, 1 also undergoes a low temperature ferroelectric-ferroelectric phase transition with an Aizu notation of 6mmF6 and small magnetic and dielectric anomalies at 171 K.