Perspective on room temperature and low-field-induced magnetoelectric coupling in molecular complexes

Abstract

Magnetoelectric (ME) coupling refers to the interaction between electric and magnetic orders in materials. Based on ME coupling, the phenomenon that an external magnetic field induces electric polarization and an external electric field induces change in mangetization can be observed and is referred to as the ME effect. Examples of the ME effect include magnetodielectric (MD), magnetoferroelectric (MF), magnetoresistence (MR) and electrically controlled magnetism effects. In recent years, the ME effect has attracted increasing attention due to the wide range of potential applications in fields such as information storage, sensors, and spintronics. The ME effect can be observed in both single-phase and composite systems but obtaining ME coupling in pure inorganic materials is extremely challenging. For example, in multiferroics with magnetism and electricity, the material must exhibit a magnetic ordered phase (ferromagnets or ferrimagnets), which coexists with the ferroelectric phase in the same temperature range. However, the materials containing both ordering phases within a single species are exceedingly rare, and those capable of coupling the two are even scarcer. MD materials are relatively easy to obtain because they are not constrained by polar point groups in their structure. With advancements in science and technology, new materials with potential ME coupling are increasingly being identified, particularly in the field of molecular materials. Molecular materials, due to their ease of design and synthesis, can not only achieve the regulation of magnetic field on polarization but also complete the control of electric field on magnetism. This paper briefly reviews recent research progress on the ME effect in molecular materials, focusing on three aspects: magnetodielectrics, magnetoferroelectrics, and electronically controlled magnetism. Typical complexes exhibiting the ME effects in these three categories are analyzed and summarized.