ANALYSIS OF FRACTAL SURFACES USING SCANNING PROBE MICROSCOPY AND MULTIPLE-IMAGE VARIOGRAPHY .2. RESULTS ON FRACTAL AND NONFRACTAL SURFACES, OBSERVATION OF FRACTAL CROSSOVERS, AND COMPARISON WITH OTHER FRACTAL ANALYSIS TECHNIQUES

This paper applies the variographic technique developed in part 1 (preceding paper in this issue) to a variety of surfaces. The results clearly show fractal regimes, and crossovers to nonfractal regimes, which agree with independent measurements. The terraced surface of graphite has nonfractal D = 2, until the onset at approximately 10(3) angstrom of marginally fractal topography with 2.0 < D < 2.1. A rougher copper surface also has nonfractal D = 2, until the onset at approximately 10(2) angstrom of fractal topography with D = 2.1 2 +/- 0.03; then at approximately 10(4) angstrom it reverts to D = 2, the result of polishing. A gold film shows nonfractal D = 2, until the onset at approximately 10(3) angstrom of fractal topography with D = 2.39 +/- 0.05. In direct comparison with other methods for fractal analysis (power spectrum, perimeter-area, and structure function/single-image variogram methods), this technique also performed the most reliably and informatively.