Anisotropy of Well Oriented

The anisotropy of the squareness of an exceedingly well oriented $\gamma {\mathrm{Fe}}_2{\mathrm{O}}_3$ magnetic tape specimen exhibiting an alignment direction squareness in 8 kOe saturating field of .875 has been measured. The field was applied at various directions in the tape plane, and the resultant magnetization and its direction were measured. The anisotropy is such that the field must be applied at least 75° to the particle alignment direction to cause the resultant magnetization to deviate 10° from that direction. Assuming a non‐interacting particle assembly, it is shown that the squareness anisotropy may be predicted quite well by a particle orientation distribution function of the form Aexp(αcos²θ) having azimuthal invariance about the alignment direction. For well‐oriented assemblies the sum of alignment and transverse squareness is shown theoretically to be approximately independent of the particular form of distribution function. Thus, except for invoking rather extreme particle interactions, the measurements preclude a planar orientation description.