DETERMINATION OF MAGNETIC ANISOTROPY AND POROSITY FROM APPROACH TO SATURATION OF POLYCRYSTALLINE FERRITES

From measurements of magnetization in the approach to saturation region of the hysteresis loop, a semiempirical method has been developed for determining reasonably accurate values of | K1 |/Ms and p eff, the fraction of nonmagnetic volume of polycrystalline ferrimagnetic materials. The technique involves the precise measurement of magnetization at five values of applied magnetic field, and the subsequent solution of four linear simultaneous equations. In combination with a measurement of the ferrimagnetic resonance linewidth, it is also shown how the intrinsic single-crystal linewidth may be estimated. The results for a variety of garnet and ferrite compositions are reported, and selected aspects of their behavior are discussed in terms of magnetic anisotropy, porosity, and linewidth. In particular, materials containing manganese appear to have large intensic linewidths, and it is considered to be highly probable that octahedral-site Mn3+ ions with short spin-lattice relaxation times are responsible for this effect. © 1969 The American Institute of Physics.