LEED Investigation on Temperature Dependence of Sublattice Magnetization of NiO (001) Surface Layers

Temperature dependence of the exchange diffraction spot intensity from the cleaved face (001) of nickel oxide is measured for the cases of very small and comparatively large penetration depth of electron beam concerning the surface barrier resonance in LEED. The exchange reflexion intensity is corrected for the Debye-Waller factors in order to reveal the temperature dependence of the sublattice magnetization. The effective critical exponent of the sublattice magnetization is determined to be 0.89±0.01 as the proper value for the top-most surface layer. The thickness of the surface layers, which is characterized by the same value of the critical exponent as the top-most surface layer, becomes thicker than the mean absorption distance when the temperature is raised up to 0.9 in T / T N .