Identification of LiNbO3, LiNb3O8 and Li3NbO4 phases by means of Raman spectrsocopy
Methodology of decoupling and estimation of Li nonstoichiometry and residual stress effects in LiNbO3 and LiTaO3 thin films is given in http://scitation.aip.org/content/aip/journal/apl/101/12/10.1063/1.4752448