Room-Temperature Magnetoelectric Coupling in Electronic Ferroelectric Film based on [(n-C3H7)4N][FeIIIFeII(dto)3] (dto = C2O2S2)

Great importance has been attached to magnetoelectric coupling in multiferroic thin films owing to their extremely practical use in a new generation of devices. Here, a film of [( n -C 3 H 7 ) 4 N][Fe III Fe II (dto) 3 ] ( 1; dto = C 2 O 2 S 2 ) was fabricated using a simple stamping process. As was revealed by our experimental results, in-plane ferroelectricity over a wide temperature range from 50 to 300 K was induced by electron hopping between Fe II and Fe III sites. This mechanism was further confirmed by the ferroelectric observation of the compound [( n -C 3 H 7 ) 4 N][Fe III Zn II (dto) 3 ] ( 2; dto = C 2 O 2 S 2 ), in which Fe II ions were replaced by nonmagnetic metal Zn II ions, resulting in no obvious ferroelectric polarization. However, both ferroelectricity and magnetism are related to the magnetic Fe ions, implying a strong magnetoelectric coupling in 1 . Through piezoresponse force microscopy (PFM), the observation of magnetoelectric coupling was achieved by manipulating ferroelectric domains under an in-plane magnetic field. The present work not only provides new insight into the design of molecular-based electronic ferroelectric/magnetoelectric materials but also paves the way for practical applications in a new generation of electronic devices.