/ M. S. Molokeev, S. V. Misyul' // Phys. Solid State. - 2012. -
Vol. 54,
Is. 1. - P. 143-154,
DOI 10.1134/S1063783412010234. - Cited References: 17. - This study was supported by the Russian Foundation for Basic Research (project no. 09-02-00062) and the Council on Grants from the President of the Russian Federation for Support of Leading Scientific Schools of the Russian Federation (grant no. NSh-4645.2010.2).
. - ISSN 1063-7834. - ISSN 1090-6460
РУБ Physics, Condensed Matter
Аннотация: The structures of two phases of the (NH4)3Nb(O2)2F4 crystal, namely, the parent cubic phase and the most distorted low-temperature phase, have been determined from data of an X-ray diffraction experiment performed for a powder sample. The profile and structural parameters have been refined according to the procedure implemented in the DDM program. The results obtained have been discussed with invoking the group-theoretical analysis of the complete order parameter condensate, which takes into account the critical and noncritical atomic displacements and allows the interpretation of the obtained experimental data. It has been found that the most probable sequence of structural transformations occurring in the crystal can be schematically represented in the following form: Fm3¯m−→−−−−(η1,η1,η)Γ+5(11−7)C2/m−→−−−−−−−−−−−−−−−−(η1,η1,η)(0,0,0,0,0,ξ,0−ξ,0,0,0,0)Γ+5(11−7)⊗Σ2(4−2)P21/m−→−−−−−−−−−−−−−−−−−−−−−−−−−−−−(η1,η1,η)(0,0,0,0,0,ξ,0−ξ,0,0,0,0)(0,0,0,0,0,ε,0,ε,0,0,0,0)Γ+5(11−7)⊗Σ2(4−2)⊗Σ3(4−3)P21/n.\begin{gathered} Fm\bar 3m\xrightarrow[{(\eta 1,\eta 1,\eta )}]{{\Gamma _5. + (11 - 7)}}C2/m\xrightarrow[{(\eta 1,\eta 1,\eta )(0,0,0,0,0,\xi ,0 - \xi ,0,0,0,0)}]{{\Gamma _5. + (11 - 7) \otimes \Sigma _2 (4 - 2)}}P2_1 /m \hfill \\ \xrightarrow[{(\eta 1,\eta 1,\eta )(0,0,0,0,0,\xi ,0 - \xi ,0,0,0,0)(0,0,0,0,0,\varepsilon ,0,\varepsilon ,0,0,0,0)}]{{\Gamma _5. + (11 - 7) \otimes \Sigma _2 (4 - 2) \otimes \Sigma _3 (4 - 3)}}P2_1 /n. \hfill \\ \end{gathered}
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Держатели документа: [Molokeev, M. S.] Russian Acad Sci, Siberian Branch, LV Kirensky Phys Inst, Krasnoyarsk 660036, Russia
[Misyul', S. V.] Siberian Fed Univ, Krasnoyarsk 660041, Russia
Доп.точки доступа: Misyul', S. V.;
Мисюль,
Сергей Валентинович; Молокеев, Максим Сергеевич
