Crystal structure study of dielectric oxynitride perovskites La{sub 1−x}Sr{sub x}TiO{sub 2+x}N{sub 1−x} (x=0, 0.2)
- Faculty of Engineering, Hokkaido University, N13W8, Kita-ku, Sapporo 060-8628 (Japan)
- Institute of Materials Structure Science, High Energy Accelerator Organization, 203-1, Shirakata, Tokai-Mura, Naka-gun, Ibaraki 319-1106 (Japan)
As is the case with SrTaO{sub 2}N, both cis-ordering of nitride anions and octahedral titling are also preferable in La{sub 1−x}Sr{sub x}TiO{sub 2+x}N{sub 1−x} (x=0, 0.2) oxynitride perovskites. A larger dielectric constant of ε{sub r}≈5.0×10{sup 3} was estimated for the pure oxynitride with x=0.2, compared with ε{sub r}≈750 for the product with x=0, by extrapolating the ε{sub r} values obtained from powders mixed with paraffin at various mixing ratios. The crystal structure of x=0.2 with larger tolerance factor than x=0 increased the octahedral tilting, which contributes to the increased dielectric constant. The increased dielectric constant supports the exchange mechanism for the dielectric property between two kinds of –Ti–N– helical coils (clockwise and anticlockwise) derived from the above cis-ordering of nitride anions. - Graphical abstract: Very large dielectric constant values were estimated for La{sub 1−x}Sr{sub x}TiO{sub 2+x}N{sub 1−x}; ε{sub r}≈5.0×10{sup 3} in x=0.2 and ε{sub r}≈750 in x=0. - Highlights: • Cis-configuration of nitride anions was confirmed in La{sub 1−x}Sr{sub x}TiO{sub 2+x}N{sub 1−x} (x=0, 0.2). • Dielectric constant values were estimated to be 750 for x=0 and 5.0×10{sup 3} for x=0.2, respectively. • The large dielectric property is to the exchange mechanism between clockwise and anticlockwise –Ti–N– coil motifs.
- OSTI ID:
- 22584078
- Journal Information:
- Journal of Solid State Chemistry, Vol. 237; Other Information: Copyright (c) 2016 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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