A semiclassical method involving surface spin waves is used to calculate the spontaneous magnetization M near the surface of a semi-infinite ferromagnet. The magnitude of the surface anisotropy constant $K_s$ introduced by Néel is assumed to be negligible compared to the magnitude of the surface anisotropy constant $K_{\mathrm{ss}}$ introduced by the present author. It is shown that under these conditions any positive value of $K_{\mathrm{ss}}$ causes the dependence of M on the temperature T to be quasilinear rather than proportional to $T^{3/2}$ and the dependence of M on position to be exponential. This surface-anisotropy-based mechanism contains a weakened-surface-exchange model as a special case. The theoretical predictions are found to provide a possible interpretation of recent experimental results on ${\mathrm{MnF}}_2$-covered Fe(110).

• Received 23 December 1988

DOI:https://doi.org/10.1103/PhysRevB.40.407