Magnetoelectricity Enhanced by Electron Redistribution in a Spin Crossover [FeCo] Complex

Abstract

Molecular-based magnetoelectric materials are among the most promising materials for next-generation magnetoelectric memory devices. However, practical application of existing molecular systems has proven difficult largely because the polarization change is far lower than the practical threshold of the ME memory devices. Herein, we successfully obtained an [FeCo] dinuclear complex that exhibits a magnetic field-induced spin crossover process, resulting in a significant polarization change of 0.45 μC cm −2 . Mossbauer spectroscopy and theoretical calculations suggest that the asymmetric structural change, coupled with electron redistribution, leads to the observed polarization change. Our approach provides a new strategy toward rationally enhancing the polarization change.

Electrically Detectable Photoinduced Polarization Switching in a Molecular Prussian Blue Analogue

“…To explore the polarization switching of the single crystals, the current during the phase transition before and after irradiation were evaluated with the pyroelectric measurement system. − A single-crystal sample was sandwiched between silver pastes on its (001) and (00–1) surfaces, which are perpendicular to the long axis of the single crystal (Figure S7a). During the thermodynamic phase transition, a negative peak for the pyroelectric current was observed at T (↓) = 145 K in the cooling process, and a peak in the opposite direction was detected in the heating process at T (↑) = 168 K, which is indicative of a polarization change.…”

Control of electronic polarization via charge ordering and electron transfer: electronic ferroelectrics and electronic pyroelectrics

“…25,93,94 The [FeCo] complex exhibits magnetoelectric effect. 95 Electric polarization switching via spin transition induced by pulsed magnetic field is observed. Polarization change via electron transfer in response to temperature and light has been also observed in a mononuclear Co valence tautomeric complex, [Co(phendiox)( rac -cth)](ClO 4 )·0.5EtOH (H 2 phendiox = 9,10-dihydroxyphenanthrene, rac -cth = racemic cth).…”

Magnetoelectric and MIESST effects in spin crossover materials exhibiting symmetry-breaking

“…The ME effect in SCO materials is a relatively new field, which has been reported in a few compounds, 74–82 including a heterometallic dinuclear complex. 83 It occurs when the magnetic field H influences the electric polarization P and dielectric constant, and/or the electric field influences the magnetization. It is important to underline that when the change of the spin state occurs between different phases, with at least one polar phase, a ME effect can be observed.…”