magnetothermal

Magnetothermal refers to processes that convert magnetic energy into thermal energy. In materials exposed to changing magnetic fields, especially alternating magnetic fields, magnetic energy can be dissipated as heat through various mechanisms depending on the material’s magnetic properties, particle size, and environment.

In nanoparticles, heating arises mainly from magnetic relaxation losses—Néel and Brownian relaxation—as well as hysteresis losses in larger ferromagnetic materials. When an alternating magnetic field is applied, magnetic moments attempt to align with the field and dissipate part of the field energy as heat.

In biomedicine, magnetothermal therapy or magnetic hyperthermia uses biocompatible magnetic nanoparticles, commonly iron oxide, introduced into tumors and heated by an external alternating magnetic field to raise temperatures near 41–46°C to damage cancer cells and sensitize them to other treatments.

Effective magnetothermal treatment depends on particle design, coating, dosing, targeting, and field parameters (frequency and amplitude). Risks include nonuniform heating, potential toxicity, and radiation safety limits for the magnetic field. Regulatory evaluation focuses on nanoparticle clearance and long-term effects.

Beyond therapy, magnetothermal effects appear in materials research and energy applications, including magnetocaloric materials that heat or cool in response to magnetic fields and magnetically assisted heating for catalysis or self-healing composites. The term is commonly used to describe any process where magnetic energy is converted to heat.