Magnetic losses in single-domain magnetic particles

Single-domain magnetic particles have unique and excellent magnetic properties and are widely used in biomedical applications, but there are many mechanisms for their response to external magnetic fields. Different models apply under various conditions, which challenges researchers who want to choose a suitable model for their studies. Based on this situation, this paper comprehensively summarizes the mechanisms and models of magnetic loss of single-domain magnetic particles in an external magnetic field. Notably, this paper comprehensively summarizes the non-equilibrium kinetic model of the response of single-domain superparamagnetic particles to external magnetic fields. In this paper, the mechanism for hysteresis loss of single-domain ferromagnetic particles and a model for its calculation are presented, the Stoner–Wohlfarth (SW) model based on equilibrium state and the statistical mechanics model based on non-equilibrium state are introduced; then, the mechanism for the relaxation loss of single-domain superparamagnetic particles and a model for its calculation are introduced, and the linear response model based on equilibrium state and the statistical mechanics model based on non-equilibrium state are introduced in a general way. Lastly, the development of single-domain superparamagnetic particles is briefly prospected. This review provides a convenient reference for researchers to explore the magnetic properties of single-domain magnetic particles and promotes their application and development in the field of biomedicine.