Fluorescence and ferroelectric microregions in KTaO3

Abstract
The near-infrared fluorescence of pure and doped KTaO3 samples is studied. In the neighbourhood of 14570 cm-1, 11 peaks are observed at 16 K and are associated with the fluorescence of a Ta3+ ion near an O vacancy. In the ferroelectric KTa0.982Nb0.0l8O3 crystal the fluorescence is not affected below Tc approximately=25 K, indicating that the Ta3+ ion in the KTaO3 material is located in a ferroelectric microdomain.