Recent progress in core–shell magnetoelectric nanomaterials: Synthesis, interface engineering, and applications

Magnetoelectric (ME) materials couple magnetic and electric polarization, enabling wireless signal transfer and actuation beyond conventional wired systems. Core–shell magnetoelectric nanoparticles (MENPs) that combine magnetostrictive and piezoelectric materials exhibit enhanced magnetoelectric coupling through efficient interfacial strain transfer and reciprocal magnetic–electric interactions. Their large interface area provides superior performance compared with bulk multiferroics and enables tunable multifunctionality. This review summarizes recent advances in the synthesis and interface engineering of core–shell MENPs, focusing on hydrothermal, microwave-assisted, sol–gel, seeded-growth, colloidal-coating, electrospinning, and ligand-mediated methods. It discusses key challenges in fabricating conformal piezoelectric shells, including lattice compatibility, surface functionalization, suppression of secondary nucleation, and shell thickness control. Applications in catalysis, wireless neural stimulation, sensing, energy harvesting, memory devices, miniature antennas, and biomedical therapy are highlighted. Finally, the review outlines remaining challenges, including scalable synthesis, robust interface design, standardized magnetoelectric characterization, and long-term biocompatibility, providing perspectives for the rational design and practical implementation of high-performance core–shell MENPs.