Growth and characterization of nonlinear optical telluromolybdate CoTeMoO 6 single crystals

Abstract Nonlinear optical (NLO) crystals CoTeMoO 6 have been grown from high temperature solution by means of spontaneous crystallization. These crystals have been characterized by temperature-dependent X-ray diffraction, infrared and electron absorption methods. Moreover, polarized Raman spectra have been measured at room temperature. These studies showed that the Mo 6+ and Te 4+ ions are in asymmetric coordination environment, and CoTeMoO 6 has the largest flexibility index among M TeMoO 6 family of telluro-molybdates ( M =Zn, Mg, Cd, Mn, Co), making this compound attractive NLO material. Raman and IR studies allowed assigning the observed modes to respective motions of atoms in the unit cell. They have also showed evidence for spin–phonon coupling at low temperatures and suggested that CoTeMoO 6 is prospective material for solid-state Raman laser-frequency converters. Analysis of electron absorption data has shown that Co 2+ ions are located in sites of weak crystal field with the crystal field parameters Dq and B equal to 548 cm −1 and 882 cm −1 , respectively.