DETECTION OF CR3+ SITES IN LINBO3MGO,CR3+ AND LINBO3CR3+

In this work, experimental results describing Cr3+ sites in LiNbO3:Cr and LiNbO3:MgO,Cr previously determined with electron-paramagnetic-resonance (EPR), electron-nuclear-double-resonance, and optical techniques, are correlated in terms of the formation of three chromium sites:Cr3+ ions in Li+ and Nb5+ positions, and a Cr3+ (Nb5+)-Mg2+ center that only appears in the double-doped system. It is concluded that the majority of the unperturbed centers, Cr3+ (Li+) and Cr3+ (Nb5+), are forming close pairs and only a small fraction of Cr3+ (Li+) ions are diluted into the crystal host, giving rise to an EPR signal.