Orbital correlations in the pseudo-cubic O and rhombohedral R-phases of LaMnO{sub 3}.
The local and intermediate structure of stoichiometric LaMnO{sub 3} has been studied in the pseudocubic and rhombohedral phases at high temperatures (300-1150 K). Neutron powder diffraction data were collected and a combined Rietveld and high real space resolution atomic pair distribution function analysis was carried out. The nature of the Jahn-Teller (JT) transition around 750 K is confirmed to be orbital order to disorder. In the high-temperature orthorhombic (O) and rhombohedral (R) phases, the MnO{sub 6} octahedra are still fully distorted locally. More importantly, the intermediate structure suggests the presence of local ordered clusters of diameter {approx} 16{angstrom} ({approx} 4 MnO{sub 6} octahedra) implying strong nearest-neighbor JT antiferrodistortive coupling. These clusters persist well above the JT transition temperature even into the high-temperature R phase.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); National Science Foundation (NSF)
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 953424
- Report Number(s):
- ANL/MSD/JA-51042; PRLTAO; TRN: US0902758
- Journal Information:
- Phys. Rev. Lett., Vol. 94, Issue 17 ; 2005; ISSN 0031-9007
- Country of Publication:
- United States
- Language:
- ENGLISH
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