Recent Advances in the Applications of Magnetic Fluids

Magnetic fluids (ferrofluids) are colloidal suspensions of magnetic nanoparticles in non-magnetic carrier liquids. They respond rapidly and reversibly to external magnetic fields, showing coupled magnetic, thermal, hydrodynamic, and optical behaviors. These properties support applications in biomedicine, mechanical engineering, environmental remediation, energy systems, and magnetooptical devices. This review summarizes recent progress in these fields, focusing on working mechanisms, performance, limitations, and key challenges such as colloidal stability, magnetic field control, scalable synthesis, and safety assessment. Magnetic fluids have strong potential as multifunctional field responsive materials, although broader practical use still depends on further improvements in stability, system design, and application oriented evaluation.