Comparison of optical properties of Cr-doped Bi12TiO20 and Fe-doped Bi12SiO20

Optical investigations of Cr-doped Bi12TiO20 were performed at T = 300, 77 and 4.2 K. An absorption line at lambda = 456 nm at T = 4.2K was detected. Line corresponds to E-5 -> T-5(2) transition of Cr2+ ion located at tetrahedral position of the sillenite cell. This conclusion was confirmed by observation of the Zeeman effect in magnetic field up to 14 T. These results for Cr-doped Bi12TiO20 are similar to those for Fe-doped Bi12SiO20. Details of the absorption line structure of Fe-doped Bi12SiO20 are explained by the Jahn-Teller effect. (C) 2018 Elsevier B.V. All rights reserved.