Abstract
The mixed compounds barium-lanthanum aluminate (BLA), and barium-neodymium aluminate (BNA), as well as their solid solutions (BLnA) have been synthetized either by solid state reactions at high temperatures or by the melting of mixtures with the following starting compositions: x2BaCO3 - x6Ln2O3 - 6 Al2O3 (1.2 ⩽ x < 1.6). In both cases the powder x-ray diffraction patterns are very similar to those of magnetoplumbite (MP) or β-alumina (β). Furthermore the new compounds present 001 (1 = 2n + 1) reflections which are forbidden in the MP and β compounds space group. By solid state reactions, pure compounds are obtained in a wide range of composition. The powder patterns of some of them exhibit extra reflections which could be attributable to an a√3 x a√3 x c superstructure. Whatever the x value, the small crystals obtained after the melting of the starting materials and cooling them, always present the approximate composition 0.43 BaO - 0.2 Ln2O3 - 6 Al2O3 as determined by electron probe micro-analysis. In this compound there is no evidence of the a√3 x a√3 x c superstructure. Diffuse reflection and electron spin resonance of Nd3+ ions in BNA and BLnA indicate that the neodymium environment is close to that found in MP type lanthanide aluminates. Ba2+ ions appear to be far from Nd3+ ions and this suggests a distribution of Ba2+ and Ln3+ ions in different and alternating 001 planes.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
