Changes in the magnetization of a recording tape produced by heating

Partial demagnetization of recording tapes has been studied and related to properties of the magnetic particles such as shape and crystalline anisotropy, and to the thermal cycling treatment of the tape. Measurements show a decrease in the remanence to saturation ratio at an elevated temperature , which is comparable to the relative demagnetization produced by heating to temperature and cooling to room temperature. The percentage decrease in each of these parameters is at least four times greater when measured normal than when measured parallel to the tape axis in the plane of the tape, whereas the decrease in the ratio of the coercive force to the saturation magnetization is essentially isotropic.