Magnetic Nanoparticle SAR: Néel vs Brownian Heating

Magnetic hyperthermia heats superparamagnetic iron-oxide nanoparticles with an alternating field so that the tissue around them warms to therapeutic temperatures (~41–46°C) while sparing surrounding healthy tissue. This simulator renders an ensemble of nanoparticles inside a 3D tissue volume and computes, from real physical constants, which of the two competing relaxation mechanisms — Néel (the internal magnetic moment flipping across the crystal's anisotropy barrier) or Brownian (the whole particle physically rotating in the surrounding fluid) — dominates the energy dissipation for the core size, AC field, and carrier medium you choose. Live readouts track both relaxation times, the effective phase lag between moment and field, the resulting specific absorption rate (SAR) in watts per gram, and a real-time M–H hysteresis loop whose enclosed area is exactly the heat delivered per field cycle.