EPR and infrared absorption study in MgO Co-Doped LiNbO3 crystals

Abstract In this work the electron spin resonance (ESR) and OH− infrared absorption spectroscopies have been used in the study of LiNbO3:Cr3+ crystals codoped with MgO. It has been confirmed that the principal defect site at low MgO concentration is the Cr3+(Li+) centre. For MgO concentration higher than 4%, Cr3+ ions located in Nb5+ site is the dominant centre. The OH− infrared absorption bands at 2827 nm and 2851 nm are attributed to the OH−−Mg2+(Nb5+) and Cr3+(Li+)-OH−− Mg2+(Nb5+) clusters respectively. Evidence supporting this assignment is presented.