Polymer Ferromagnetism: Revealing Mechanisms and Future Prospects through Radical, Charge-Transfer, and Polaron Methods

Ferromagnetic organic polymers show great potential in spintronics, flexible electronics, and biomedicine due to their lightweight flexibility, biocompatibility, and solution processability. However, existing materials face challenges including insufficient room-temperature magnetic performance and unclear structure–property relationships. This perspective systematically classifies ferromagnetic polymers into three categories based on spin carrier introduction mechanisms: radical-type, charge-transfer-type, and polaronic ferromagnets. Radical polymers achieve high M S (∼1 emu·g –1 ) but face stability issues. Charge-transfer polymers utilize charge transfer between donor–acceptor units to induce open-shell high-spin states, thereby demonstrating excellent synergistic optoelectromagnetic properties. Polaronic ferromagnets enable an intrinsic magnetism-conductivity combination via doping. Analysis indicates three-dimensional spin network construction, electronic configuration mixing enhancement, and precise doping control as critical strategies for performance improvement. Based on current development trends, this review provides insights for achieving the transition of ferromagnetic polymer materials from laboratory research to practical applications.