Ilmenite-like stacking defect in nonstoichiometric lithium niobate crystals investigated by Raman scattering spectra

Autor: Cunzhou Zhang, Yongfa Kong, Xiaojun Chen, Wanlin Zhang, Guangyin Zhang, Jingjun Xu
Rok vydání: 2000
Předmět:
Zdroj: Journal of Applied Physics. 87:4410-4414
ISSN: 1089-7550
0021-8979
Popis: The Raman spectra of three pure lithium niobate (LiNbO3) crystals with different content of Li and several doped LiNbO3 (Mg, In and Ti) crystals have been investigated. A weak peak at about 738 cm−1 reported as a very strong Raman peak of ilmenite phase LiNbO3 was observed for nonstoichiometric LiNbO3 crystals. The dependence of this peak on Li content and doping concentration in crystal suggested that there is a new kind of defect structure which has ilmenite-like stacking and direct relationship with antisite NbLi4+ ion. This result experimentally proved the existence of ilmenite-like stacking defect in nonstoichiometric LiNbO3 for the first time. This defect is in good agreement with the Li vacancy model and has a different structure from that proposed by Smyth [Ferroelectrics 50, 93 (1983); Proc. IEEE, p. 115 (1986)].
Databáze: OpenAIRE