[2] [2] Sanghera J S, Aggarwal I D. Journal of Non-Crystalline Solids, 1999, (256-257): 6.

[3] [3] Turnbull D A, Sanghera J S, Nguyen V Q. Materials Letters, 2004, 58(1-2): 51.

[4] [4] Cardinal T, Richardson K A, Shim H. Journal of Non-Crystalline Solids, 1999, (256-257): 353.

[5] [5] Guorong C, Jinjian C. Journal of the American Ceramic Society, 1998, 81: 1695.

[6] [6] Tao H, Dong G, Zhai Y. Solid State Communications, 2006, 138(10-11): 485.

[8] [8] Balakrishnan M, Kozick M N, Poweleit C. Journal of Optoeletronics and Advanced Materials, 2007, 9: 3241.

[9] [9] Asami T, Matsuishi K, Onari S, et al. Journal of Non-Crystalline Solids, 1998, 226 (1-2): 92.

[10] [10] Asami T, Matsuishi K, Onari S, et al. Journal of Non-Crystalline Solids, 1997, 211(1-2): 89.

[12] [12] Fayek S A. Infrared Physics & Technology, 2005, 46(3): 193.

[13] [13] Kotsalas I P, Papadimitriou D, Raptis C. Journal of Non-Crystalline Solids, 1998, 226: 85.

[14] [14] Savova E, Skordeva E, Vateva E. Journal of Physics and Chemistry of Solids, 1994, 55(7): 575.

[15] [15] Tauc J, Menth A. Journal of Non-Crystalline Solids, 1972, (8-10): 569.

[16] [16] Koudelka L, Frumar M. Journal of Non-Crystalline Solids, 1980, 41: 171.

[17] [17] Takebe H, Hirakawa T, Ichiki T. Journal of the Ceramic Society of Japan, 2003, 111: 572.

[18] [18] Lin C, Tao H, Wang Z. Journal of Non-Crystalline Solids, 2009, 355(7): 438.

[19] [19] Petit L, Carlie N, Adamietz F. Materials Chemistry and Physics, 2006, 97(1): 64.

[20] [20] Wang X F, Gu S X, Yu J G. Solid State Communications, 2004, 130(7): 459.

[21] [21] Zhong Boqiang. Journal of Non-Crystalline Solids, 1987, (95-96): 295.

[22] [22] Nazabal V, Němec P, Jurdyc A M. Thin Solid Films, 2010, 518(17): 4941.

[23] [23] Pan R K, Tao H Z, Zang H C. Journal of Non-Crystalline Solids, 2011, 357 (11-13): 2358.