Raman and Mössbauer study of the pseudo-orthorhombic-to-tetragonal phase transition in YBa2(Cu1-xFex)3O7-δ (0.02≤x≤0.15) (EN)

Bozukov, L (EN)

Tihov, J (EN)

Hadjiev, VG (EN)

Iliev, M (EN)

Atanassova, Y (EN)

Liarokapis, E (EN)

The polarized Raman spectra from microcrystals of YBa2(Cu1-xFex)3O7-δ (0.02≤x≤0.15) were studied in various scattering configurations allowing one to follow the variations with x of both diagonal (Ag) and non-diagonal (B2g and B3g) Raman modes. It was found that the splitting of the strongest in intensity B2g, B3g Raman pair at 210 and 300 cm-1 associated with O(4) vibrations along a and b, respectively, decreases slightly with x, thus indicating that in a microscopic scale the structure remains orthorhombic over the whole substitutional range. The Mössbauer spectra for x=0.05, 0.10, and 0.15 showed a superlinear increase of the number of five-fold oxygen-coordinated Fe-atoms at the Cu(1)-sites. This is consistent with the assumption that Fe-clusters are formed along the <110> microtwin boundaries at higher x. In this sense YBa2(Cu1-xFex)3O7-δ could be considered as a two-phase system. The observed splitting of the Ag Raman mode of Ba at x≥0.07 supports such an assumption. The Fe substitution increases the local disorder thus including additional Raman scattering of one-phonon density-of-states origin with a maximum at 580 cm-1. © 1992. (EN)

journalArticle (EN)

Yttrium Barium Copper Iron Oxides (EN)

Ceramic Materials (EN)

Spectroscopy, Raman (EN)

Spectroscopy, Mossbauer (EN)

High Temperature Superconductors (EN)

Oxide Superconductors (EN)

Phase Transition (EN)

Yttrium Compounds--Phase Transitions (EN)

National Technical University of Athens

Digital Library of National Technical University of Athens | Dspace@NTUA

Κεντρική Βιβλιοθήκη Ε.Μ.Π.

Ιδρυματικό Αποθετήριο

Δημοσιεύσεις μελών Δ.Ε.Π. σε περιοδικά

Physica C: Superconductivity and its applications (EN)

1992 (EN)

http://hdl.handle.net/123456789/10800

10.1016/0921-4534(92)90939-A (EN)

09214534 (EN)

191 (EN)

3-4 (EN)

428 (EN)

419 (EN)