ИСТИНА

It is known that magnetizable bodies and magnets can levitate in vessels with magnetic fluid (MF). In this paper, a heavy spherical magnet levitating due to magnetic forces in a MF drop on a horizontal plane is investigated theoretically and experimentally. Two cases are considered: without an applied magnetic field and with applied vertical uniform field (Fig 1). In the experiments, the height of the magnet levitation is measured depending on the MF volume. In the first case (without magnetic field), where the magnetic moment of the magnet is perpendicular to the bottom, here we obtain that the magnet in the MF orients it’s magnetic moment horizontally, parallel to the plane. In the second case, even a small magnetic field orients the magnetic moment vertically, along the direction of the field. Theoretically, we determine the MF shape, calculate the force acting on the magnet and find the height of the magnet levitation. In theory, the experimentally measured nonlinear dependence of the MF magnetization on the magnetic field is taken into account. In both cases, the magnet levitates high enough (at a distance nearly eqauls to a magnet radius from the horizontal plane). The levitation height increases with an increase in the MF volume both in theory and in experiment. It is shown that the theoretical solution proposed here describes the experiment better than the theory with constant magnetic permeability proposed previously. The research was supported by the RSF grant (project No. 20-71-10002-P).