Rotational hysteresis in particles for magnetic recording with different switching modes

The rotational hysteresis analysed in fine particles used in magnetic recording media is reported and compared with the expected behaviour for coherent and incoherent cooperative reversal modes. The analysed materials are particles which are modified with the addition of doping ions, which induces an evolution of the magnetization reversal towards more incoherent and heterogeneous mechanisms. The rotational hysteresis energy loss W-r and its dependence on the applied field evolve in agreement with the behaviour expected from the evolution of the reversal mode.