The schematic illustrates the heat generation mechanisms of magnetic nanoparticles (MNPs) under an alternating magnetic field (AMF). Upon exposure to AMF, the magnetization vector (M) of the MNPs undergoes relaxation processes that result in heat dissipation. At low thermal stability (low σ = KeffV/kBT), Néel relaxation dominates, where spin-orbit coupling induces lattice vibrations. At high thermal stability (high σ), Brownian relaxation occurs as the physical rotation of the MNPs generates frictional heat in the surrounding medium. These combined effects of Néel and Brownian relaxation contribute to efficient heat dissipation, which is critical for advanced applications such as multiplexed neural stimulation.
- Mingu Song
- Dowoo Kim
- Heon-Jin Choi
