Surface magnesium of iron borate

Surface magnetism - a macroscopic transition magnetic layer due to surface magnetic anisotropy, is observed and invesigated in the natural nonbasal faces of iron borate (FeBO2) single crystals by the magneto-optical technique. The anisotropy is the result of a change in symmetry of the surface magnetic ion surroundings. Erasure of surface magnetism at a face of the (1014) type occurs in a field Her ∼ 1.6 kOe. The surface anisotropy energy for the (1014) and (1120) faces is calculated. The theory describes the symmetry of the magnetic anisotropy, and the calculated values of the field Hcr in order of magnitude are the same as those measured