Fig. 1.

Classification and properties of magnetic nanoparticles. (a) Typical $\stackrel{\rightharpoonup }{M}-\stackrel{\rightharpoonup }{H}$ curve of (left) ferromagnetic (FM) and (right) superparamagnetic (SPM) particles, where the hysteresis loop and remnant magnetization (${\stackrel{\rightharpoonup }{M}}_r$) is present in the FM particles. (b) Schematic of the sample arm in a MM-OCT setup where (left) MNP-laden tissue is located beneath the magnetic coil. (Left) The magnetic force on the tissue and (right) different forms of magnetomotion are illustrated in relation to the OCT imaging beam (adapted from [11, 21]). (c) Heating mechanisms of SPM nanoparticles, where (left) Néel rotation describes the internal rotation of the magnetic moment (shown as arrows), and (right) Brownian rotation is the rotation of the entire particle.