Comparison of volume distribution of magnetic nanoparticles obtained from M-H curve with a mixture of log-normal distributions

We studied the distributions of the magnetic moment and magnetic volume of magnetic nanoparticles (MNPs). These distributions were estimated by applying the singular value decomposition method to the M-H curve measured in the liquid phase. The estimated distributions were compared with a mixture of log-normal distributions, and two results agree well with each other. Using the estimated distribution of the magnetic moment, we also analyzed the M-H curve of immobilized MNPs in order to estimate the average value of the anisotropy energy constant Ku and the characteristic time τON that determines the Neel relaxation of immobilized MNPs. The values Ku and τON are estimated as 4 kJ/m³ and 1×10-9 s, respectively, for Resovist MNPs.