On the unsuitability of a vibrating sample magnetometer for measuring the magnetization curves of magnetic fluids

Abstract

The magnetization curves of magnetic fluid samples were measured using a vibrating sample magnetometer (VSM) and the differential run method. For standard magnetic fluids, the VSM gives significantly underestimated values of magnetization. In the case of a solid sample of a magnetic fluid based on epoxy resin, there is a complete coincidence of the magnetization curves obtained by the two measurement methods. The last experiment was performed with a styrene-based sample. It was initially measured with the use of the VSM in a liquid state. Then the sample was polymerized (without being removed from the magnetometer) and repeated measurements were performed. The magnetization curve of the liquid sample was noticeably lower than that of the polymerized sample.