First-order reversal curves of magnetic recording tapes

The interaction and its variation between magnetic grains in two kinds of magnetic recording tapes are investigated by first-order reversal curves (FORC) and the δM method. The composition and microstructure of the samples are characterised by x-ray diffraction and scanning electron microscope. The FORC diagram can provide more accurate information of the interaction and its variation, but the δM curves cannot. The positive interaction field and the large variation of the interaction field have opposite effects on the δM curve. (condensed matter: electronic structure, electrical, magnetic, and optical properties)