I am investigating thin SixC1-x films by ESR. It is possible that the entire film is under tensile or compressive stress. How would this be expected to affect the ESR measurement in comparison to an unstressed sample? (g-factor of ESR centers, linewidth, etc...). Is the shift generally in one direction, i.e. increase of g-factor with tensile and decrease of g-factor with compressive stress for example?
If ESR signals are anisotropic (angular dependent), one can extract the strain or distortion from the simulation of angular dependent resonance field,
The ESR line width is very likely to broaden. The stress in the film will increase in-homogeneity in the film which in turn increases the g-factor distribution and therefore the line width.
A shift may occur, for example, if the in-homogeneity created in the materials enhanced the intensity of lower g-value paramagnetic centers and decrease the intensity of the paramagnetic centers with higher g-value.
There are probably several competing mechanisms which would change the ESR line due to stress in a film. I think broadening of the line-width is most likely and easiest effect to guess in a stressed film.
The strains will, most probably, broaden lines in the anisotropic manner. In some cases, this anisotropy may be averaged to some extent by the paramagnetic particle translation or rotation motion. Then the averaged anisotropy become a measure of the very slow motions.
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