Growth and ferroelectric domain control of homogeneous MgO-doped near-stoichiometric lithium niobate single crystals by melt-supplying technique

MgO-doped near-stoichiometric lithium niobate single crystals (MgSLN) are one set of important materials used as periodic poled quasi-phase matching ferroelectrics for the application of NLO wavelength conversion. For NLO application, high homogeneity of both lithium and magnesium in the bulk crystal is essential. In this work, MgSLN was grown by a melt-supplying technique that had been used to grow near-stoichiometric lithium niobate single crystals. Firstly, the effective segregation coefficient of MgO in Li-rich solution was tested. Then homogeneous MgSLN with diameter of 2 inches was grown with composition variation as follows: Delta[MgO]<0.02 mol%/cm, Delta[Li2O]<0.005 mol%/cm. For MgSLN, our study showed that its Curie temperature was very close to its melting temperature, its poling technique was different from that of the congruent lithium niobate crystals. The etching morphologies and UV absorption spectra of as-grown crystals were also reported. (C) 2007 Elsevier B.V. All rights reserved.