Crystal structures of BaMgF_4-xO_x/2 thin films

Abstract

A chemical deposition method has been employed to synthesize BaMg₄ thin films. Crystal structures of the grown thin films were found to be sensitive to thermal treatment conditions. Only the thin films heated at 550°C for 1 to 2 hours exhibited BaMgF₄-type structure. Surface composition analysis indicated that anions in the thin films contained not only fluorine ions, but oxygen ions as well. The virtual composition of the thin films is thus BaMg_4-xO_x/2, instead of BaMgF₄. The phase transformation and the crystal structures of BaMgF_4-xO_x/2 thin films at different synthesized temperatures were investigated. A new cubic structure of BaMgF_4-xO_x/2 was identified.

Keywords:

• crystal structure
• phase transformation
• thin film