Paramagnetic trigonal center production in yttria-stabilized zirconia by electronic excitations

Electron paramagnetic resonance (EPR) spectroscopy is used to study the point defect production in yttria-stabilized zirconia (YSZ) (1 0 0) single crystals by swift heavy ion, electron and X-ray irradiations. A common color center known as the “T center” (for “trigonal” center) with an axial 〈1 1 1〉 symmetry is produced in all cases. We show that this defect is likely an intrinsic one with concentrations much larger than the major impurities. The growth curves of this point defect versus fluence for ion and electron irradiations can be on the whole rescaled as a function of the absorbed dose. This confirms that T centers are produced by the electronic excitations, either at low density with X-rays and electrons, or at high density with heavy ions. A kinetic model depending on fluence is proposed to account for the saturation behavior of growth curves. The production rate, corresponding to the initial slope of growth curves, increases steeply versus the average volume density of electron–hole pairs that are generated by ions and electrons in the irradiated volume.