Xinwei Dong

Inorganic–organic hybrid molecular multiferroic and magnetoelectric materials, similar to multiferroic oxide compounds, have recently attracted increasing attention because they exhibit diverse architectures, a flexible framework, fascinating physics, and potential magnetoelectric functionalities in novel multifunctional devices such as energy transformation devices, sensors, and information storage systems. Herein, the classification of multiferroicity and magnetoelectricity is briefly outlined and then the recent advances in the multiferroicity and magnetoelectricity of inorganic–organic hybrid molecular materials, particularly magnetoelectricity and the relevant magnetoelectric mechanisms and their categories are summarized. In addition, a personal perspective and an outlook are provided.

The motion of transverse domain walls (DWs) in U-shaped ferromagnetic nanotube which owns two different geometric confinements were investigated by micromagnetic simulation. Driven by unidirectional magnetic fields, the chirality-dependent DW structure and velocity under low fields and two phases of chiral Walker breakdown processes under high fields were observable, respectively. All these chirality-dependent behaviors can be attributed to the different dynamics of magnetizations in geometric confinements. Additionally, DW structures have different responses and sensitivity to applied fields, leading to a hierarchy and complex Walker breakdown processes. This supplies a new perspective for manipulating DW chirality.

Magnetoelectric materials with a large magnetoelectric response, a low operating magnetic (or electric) field, and a room‐temperature (or higher) operating temperature are of key importance for practical applications. However, such materials are extremely rare because a large magnetoelectric response often requires strong coupling between spins and electric dipoles. Herein, an example of a magnetoelectric composite is prepared by using a room‐temperature multiaxial molecular–ionic ferroelectric, tetramethylammonium tetrachlorogallate(III) (1). Investigation of the magnetoelectric effect of the magnetoelectric laminate composite indicates that its room‐temperature magnetoelectric voltage coefficient (α_ME) is as high as 186 mV cm⁻¹ Oe⁻¹ at H_DC = 275 Oe and at the H_AC frequency of ≈39 kHz, providing a valid approach for the preparation of magnetoelectric materials and adding a new member to the magnetoelectric material family.

The propagations of domain walls (DWs) in L-shaped nanostrips under unidirectional fields were investigated by micromagnetic simulations. The DWs’ transmission fields, moving speeds, and width variations are all chirality-dependent. From the viewpoint of magnetic charge distribution, these phenomena can be attributed to the near-field and chirality-dependent interaction between the DWs (behaving as a magnetic charge pair) and the corner (having two different charge pairs). With increasing corner inner radius, the chirality dependence becomes weak and even disappears at a large inner radius of 1000 nm.