Analytic solution for magnetic orientation between grains

Transmission electron microscopy experiments have shown that CoCrTa films f or hard disk drives experience chromium segregation at grain boundaries. Th e resultant changes in the ferromagnetic parameters of the material togethe r with the variation in the anisotropy direction from grain to grain are de termining factors governing its magnetic behavior. In this paper, the case of two grains, differing in the direction of their magnetic anisotropy and possessing a change in their material content at the interface which we mod el by a Gaussian distribution, is solved analytically. Effects due to the d iffuse interface such as localized regional changes in the anisotropy, exch ange energy, and magnetic moment are included using perturbation theory. On e of the outputs is the profile of the magnetization orientation in the inh omogeneous medium-thus yielding the smoothness and extent of the change. Su ch knowledge, in addition to its intrinsic scientific interest, points the direction, both for large scale computer calculations and for media improve ment.