Magnetic long- and short-range order at the surface of ferromagnets

The long- and short-range order at the surface of ferromagnets is studied. The Ising model for S=1/2 is solved in the Bethe approximation. Allowing different magnetic coupling at the surface, the necessary condition for a higher surface critical temperature TCS than that in the bulk is analyzed. Results are given for the magnetization and the short-range order at the fcc (111) and (110) surfaces of crystals for several cases. The effect of surface magnetization on the rate of H₂ desorption is briefly discussed.