Line broadening mechanisms analysis

The DISPA analysis described above is based on comparison of an experimental curve to a reference circle. Although that display is qualitatively useful in identifying the correct line-broadening mechanism, the analogous Cole-Cole plotS in dielectric relaxation continues as a popular display mode after nearly 40 years), a display in vyhich the same experimental DISPA data is compared to a straight line could better help to determine quantitatively the line-broaoen-ing parameter(s) of that mechanism. 

X-ray and electron diffraction methods are applied in order to measure atomic distances in the crystal lattice and their changes. Hence, the diffraction methods are also basically suitable for measuring the strain/stress behaviour in thin films. However, since the film thickness and the crystallite size in thin films are small, some line broadening already arises from this. In order to determine what contribution the mechanical stresses have on the diffuse lines, careful analysis of the line profiles must be undertaken [148, 151]. This method is less suitable for routine determination of stresses in thin films. In some cases, it is possible though rarely applied to determine the stresses in the films through their influence on other, known film properties, at least approximately. Such properties are, for example, the position of an absorption edge [152], the Hall effect [153], electron spin resonance spectra [155] and in the case of superconducting films, variations in the critical transition temperature [156]. However, these effects can, unfortunately, also arise for other reasons, and thus these techniques can usually only be used as supplemental experiments. 

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