High-Temperature Phase Transitions Preceding the Decomposition of Mixed Valence Aluminum Titanate Pseudobrookite

• DOI: 10.1021/acs.cgd.3c01043
• Publication Date: 2024-01-08T16:27:30Z
• Authors: Davor Tolj; WenHua Bi; Yong Liu; Ivica Živković; Henrik M. Rønnow; Arnaud Magrez
• Keywords: Orthorhombic crystal system; Negative Thermal Expansion

Dark blue single crystals of Al1.753+Ti1.04+Ti0.253+O5 were grown with a novel synthesis method based on the reaction Ti3+/Ti4+-containing langbeinite melt and porous α-alumina crucible. The obtained needles crystallize in pseudobrookite structure and, upon heating, undergo two reversible phase transitions, from orthorhombic Cmcm to C2/m first subsequently C2 symmetry. Like known aluminum titanate pseudobrookites, anisotropic thermal expansion is observed. temperature evolution crystal reveals insights into mechanism leading decomposition pseudobrookites above 725 °C. magnetic electrical properties are discussed compared other reported pseudobrookites.