THE VECTOR MAGNETIC-FIELD DEPENDENCE OF THE MAGNETIC-MOMENT OF PARTICULATE RECORDING MEDIA

The magnetic moment for a gamma-Fe2O3:Co recording media was measured as functions of strength and direction of applied field. Fourier expan sions on the component of magnetic moment along the applied field dire ction (m(x)) to the rotation angle (theta) show that the zeroth, first , and second order coefficients are related to the reversible part, re manent part, and irreversible susceptibility, respectively. The calcul ated effective angle between the magnetic moment and the applied field (alpha) consistently equals zero at theta congruent to 134 degrees an d theta congruent to 304 degrees for the decreasing- and increasing-fi eld measurements, respectively. The (theta-alpha) vs theta curves corr espond to those predicted by the texture model. (C) 1996 American Inst itute of Physics.