Static sample magnetometer: a new characterization method for low permeability materials and ferrofluids

In this paper, an original magnetometer dedicated to static sample characterization is proposed. It is especially designed for ferrofluids whose behaviors are sensitive to the magnetic field and for which the classic methods using a mobile sample are no more suitable. The magnetometer can also be used to test any feebly permeability material. The paper outlines the characterization device and its use in four sections. The first describes the principle of the measurement and the physical and mathematical approach for the reconstruction of the $J(H)$ curve. The second develops the magnetometer design, practical realization, and calibration. In the third section, a numerical validation of the magnetometer and $J(H)$ construction is performed owing to finite element simulation of the magnetometer. Finally, an experimental validation is investigated on a solid specimen made of a weak permeability iron composite. The results are compared with those achieved with an extraction magnetometer and show a good agreement as the differences observed reach a few percent.