Construction of Magnetoelectric Composites with a Large Room‐Temperature Magnetoelectric Response through Molecular–Ionic Ferroelectrics

Abstract 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.