In situ measurement of pressure and strain effects in corundum ceramics

An Equipement has been built for the generation of uniaxial pressure and of bending stress respectivety directly in the cavity of an X-band ESR spectrometer. Changes of the structure of paramagnetic centres (Fe 3+ on Al 3+ sites) could be detected in materials with a high content of corundum under the innuence of pressure and bending stress. The objects of investigation are not only suitable model system but also have practical relevance. The Fe 3+ -ions, incorporated in the materials react very sensitive on mechanically or thermally induced changes of the state of the matrix. They give insight into the materials at a microscopic level The interpretation of the observed intensity and shift effects is possible on the basis of an adequate spin-hamiltonian.