Pressure‐induced structural transformations in In2‐xYx(MoO4)3 systems. (15th October 2015)

• Record Type: Journal Article
• Authors: Mendonça, R.; Paraguassu, W.; Mendes Filho, J.; Marinkovic, B. A.; Souza Filho, A. G.; Maczka, M.; Freire, P. T. C.
• Is Part Of: Journal of Raman spectroscopy. Volume 47:Number 3(2016)
• Page Start: 350
• Page End: 356
• Publication Date: 2015-10-15
• Subjects: triple molybdates -- phase transition -- negative thermal expansion -- pressure‐induced amorphization; Raman spectroscopy -- Periodicals; 535.846
• DOI: 10.1002/jrs.4814
• Languages: English
• ISSNs: 0377-0486

Abstract

Abstract : In this work, we report results of high‐pressure Raman experiments (P < 8 GPa) on In2‐x Yx Mo3 O12 for x = 0.0 and 0.5. A crystalline to crystalline structural phase transition and pressure‐induced amorphization (PIA) have been identified. The structural phase transition takes place at 1.5 and 1.0 GPa for In2 (MoO4 )3 and In1.5 Y0.5 (MoO4 )3, respectively, resulting in the change of structure from monoclinic P21 /a to a more denser structure. The PIA started at 5 and 3.4 GPa for In2 Mo3 O12 and In1.5 Y0.5 Mo3 O12, respectively. The amorphization process takes place in two stages in the case of In1.5 Y0.5 Mo3 O12 phase, while for In2 Mo3 O12, it is not complete until the pressure is as high as 7 GPa. Our results also suggest that with increase of ionic size of the A 3+ ions, the octahedral distortion increases and consequently larger local structural disorder is introduced in the A2 (MoO4 )3 system, where A is a trivalent ion (In, Y 3+, Sc 3+, Fe 3+, etc.). Copyright © 2015 John Wiley & Sons, Ltd. Abstract : High‐pressure Raman experiments on In2‐x Yx Mo3 O12 reveal a crystalline to crystalline structural phase transition at low‐pressure values and a pressure‐induced amorphization at higher pressures. The first transformation leads the structure from monoclinic P21 /a to a more denser structure. The amorphization process takes place in two stages for In1.5 Y0.5 Mo3 O12, while for In2 Mo3 O12, it is not complete until the pressure is as high as 7 GPa. With increase of ionic size of the trivalent cation, the octahedral distortion increases.