Vector magnetisation of recording media: a new method to compensate for demagnetising fields

Until now measurements of M(H) loops of thin samples have been corrected for demagnetization after completion of the measurement. In this way, it is possible to correct for the component of the demagnetizing field which is parallel to the applied field. The authors present a method to correct for the total demagnetizing field during the measurement by simultaneously changing the strength of the applied field and rotating the sample. This method has been applied to a sample of metal-evaporated (ME) tape and a Co-Cr layer. These measurements show that the method is significantly better than existing methods. It is shown that the intrinsic magnetic properties of the ME tape and the Co-Cr layer measured with the method are remarkably similar.>