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 K-u and the characteristic time tau(ON) that determines the Neel relaxation of immobilized MNPs. The values K-u and tau(ON) are estimated as 4 kJ/m(3) and 1 x 10(-9) s, respectively, for Resovist MNPs. (C) 2015 AIP Publishing LLC.