Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1526674 | Materials Chemistry and Physics | 2008 | 6 Pages |
Abstract
A series of RMnO3 samples with R = Sc, Y, Dy-Lu was synthesized through a two-step route in which first the hexagonal oxides, h-RMnO3, were prepared under normal pressure using an EDTA method and then converted to orthorhombic perovskites, o-RMnO3, through a high-pressure treatment at 5 GPa and 800 °C. Since all the aforementioned members but the R = Sc member were converted to an orthorhombic perovskite phase under the 5-GPa high-pressure condition, an additional sample of InMnO3 of the hexagonal structure was prepared and tested for the high-pressure conversion. The stability limit of the orthorhombic perovskite structure under the 5-GPa high-pressure condition was concluded to be located between InMnO3 and LuMnO3 in terms of the size of the A-site cation constituent, RIII or InIII. The decrease in the size of RIII was found to increase the distortion of o-RMnO3 with a decrease in the MnOMn bond angle from 144.3° for Dy to 140.3° for Lu. All the hexagonal and orthorhombic RMnO3 phases exhibited antiferromagnetic characteristics at low temperatures.
Keywords
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Physical Sciences and Engineering
Materials Science
Electronic, Optical and Magnetic Materials
Authors
K. Uusi-Esko, J. Malm, N. Imamura, H. Yamauchi, M. Karppinen,