An Improved Method for Estimating the Saturation Magnetization and Core Size Distribution of Magnetic Nanoparticles Based on M-H Curve

The saturation magnetization and core size distribution of magnetic nanoparticles (MNPs) play an important role in biomedical and biological applications. Fast and precise estimation of the saturation magnetization and core size distribution are critical. The core size distribution of MNPs can be determined from the static magnetization (M-H curve) obtained by a vibrating sample magnetometer (the M-H curve consists of a saturated region and an unsaturated region). However, the method is time-consuming, the number of sampling points and the field strength range have a large influence on the estimation result of the distribution, it is necessary to find the optimal number of sampling points and magnetic field strength range, and the saturation magnetization needs to be obtained from the saturated region before determining the distribution. We compared the two methods [geometric series sampling (GSS) and arithmetic series sampling (ASS)] for the M-H curve to reduce the field strength range and the number of sampling points, and the saturation magnetization and core size distribution can be estimated with the unsaturated region of M-H curve. The experimental results show that the saturation magnetization and the core size distribution of MNPs can be estimated more quickly and precisely using GSS in comparison to ASS.