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Title: Checkerboard-ordered pattern of Bi{sub 0.5}Sr{sub 0.5}MnO{sub 3} low-temperature phase probed by x-ray resonant scattering

Abstract

Resonant x-ray scattering (RXS) at the Mn K edge has been used to characterize the low temperature ordered phase of Bi{sub 0.5}Sr{sub 0.5}MnO{sub 3}. Strong resonances were observed for the (030), (050), (05/20), (0 7/2 0), (4 (1/2) 0), and (3 (1/2) 0) reflections as the photon energy is tuned through the Mn K edge. The reported azimuthal and polarization dependence of the resonant intensities indicates that the low temperature phase is described as a checkerboard ordering of two types of Mn sites with different local geometrical structures. One of the sites is anisotropic, a tetragonal distorted oxygen octahedron and the other one is isotropic, a nearly undistorted oxygen octahedron. The distinction of these two Mn sites is accompanied by a displacement of the Mn atoms transverse to the b axis. We conclude that this checkerboard-ordered pattern is a common ground state in half-doped manganites. Intermediate valence states according to fractional charge segregation were deduced for the two nonequivalent Mn atoms, far from the localized Mn{sup 3+} and Mn{sup 4+} ionic species. Hence, the experimental data discard the ionic model of charge and orbital ordering of localized 3d (or 3d-like) states at the Mn site (or the MnO{sub 6} cluster).more » We suggest a description of the RXS in terms of band structure effects and lattice dynamics.« less

Authors:
; ;  [1]; ;  [2];  [3]
  1. Instituto de Ciencia de Materiales de Aragon, Departamento de Fisica de la Materia Condensada, CSIC-Universidad de Zaragoza, C/Pedro Cerbuna 12, 50009 Zaragoza (Spain)
  2. Institut de Ciencia de Materials de Barcelona, CSIC, Campus Universitari de Bellaterra, E-08193 Bellaterra (Spain)
  3. Institute of Chemical Technology, Technicka 5, 16628 Prague 6 (Czech Republic)
Publication Date:
OSTI Identifier:
20788190
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. B, Condensed Matter and Materials Physics; Journal Volume: 73; Journal Issue: 20; Other Information: DOI: 10.1103/PhysRevB.73.205107; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANISOTROPY; ATOMS; BISMUTH COMPOUNDS; DOPED MATERIALS; GROUND STATES; JAHN-TELLER EFFECT; MAGNETORESISTANCE; MANGANATES; MANGANESE IONS; OXYGEN; PHOTONS; POLARIZATION; REFLECTION; RESONANCE; RESONANCE SCATTERING; STRONTIUM COMPOUNDS; TEMPERATURE DEPENDENCE; VALENCE; X RADIATION; X-RAY DIFFRACTION

Citation Formats

Subias, G., Garcia, J., Sanchez, M. C., Beran, P., Garcia-Munoz, J. L., and Nevriva, M.. Checkerboard-ordered pattern of Bi{sub 0.5}Sr{sub 0.5}MnO{sub 3} low-temperature phase probed by x-ray resonant scattering. United States: N. p., 2006. Web. doi:10.1103/PHYSREVB.73.2.
Subias, G., Garcia, J., Sanchez, M. C., Beran, P., Garcia-Munoz, J. L., & Nevriva, M.. Checkerboard-ordered pattern of Bi{sub 0.5}Sr{sub 0.5}MnO{sub 3} low-temperature phase probed by x-ray resonant scattering. United States. doi:10.1103/PHYSREVB.73.2.
Subias, G., Garcia, J., Sanchez, M. C., Beran, P., Garcia-Munoz, J. L., and Nevriva, M.. Mon . "Checkerboard-ordered pattern of Bi{sub 0.5}Sr{sub 0.5}MnO{sub 3} low-temperature phase probed by x-ray resonant scattering". United States. doi:10.1103/PHYSREVB.73.2.
@article{osti_20788190,
title = {Checkerboard-ordered pattern of Bi{sub 0.5}Sr{sub 0.5}MnO{sub 3} low-temperature phase probed by x-ray resonant scattering},
author = {Subias, G. and Garcia, J. and Sanchez, M. C. and Beran, P. and Garcia-Munoz, J. L. and Nevriva, M.},
abstractNote = {Resonant x-ray scattering (RXS) at the Mn K edge has been used to characterize the low temperature ordered phase of Bi{sub 0.5}Sr{sub 0.5}MnO{sub 3}. Strong resonances were observed for the (030), (050), (05/20), (0 7/2 0), (4 (1/2) 0), and (3 (1/2) 0) reflections as the photon energy is tuned through the Mn K edge. The reported azimuthal and polarization dependence of the resonant intensities indicates that the low temperature phase is described as a checkerboard ordering of two types of Mn sites with different local geometrical structures. One of the sites is anisotropic, a tetragonal distorted oxygen octahedron and the other one is isotropic, a nearly undistorted oxygen octahedron. The distinction of these two Mn sites is accompanied by a displacement of the Mn atoms transverse to the b axis. We conclude that this checkerboard-ordered pattern is a common ground state in half-doped manganites. Intermediate valence states according to fractional charge segregation were deduced for the two nonequivalent Mn atoms, far from the localized Mn{sup 3+} and Mn{sup 4+} ionic species. Hence, the experimental data discard the ionic model of charge and orbital ordering of localized 3d (or 3d-like) states at the Mn site (or the MnO{sub 6} cluster). We suggest a description of the RXS in terms of band structure effects and lattice dynamics.},
doi = {10.1103/PHYSREVB.73.2},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
number = 20,
volume = 73,
place = {United States},
year = {Mon May 15 00:00:00 EDT 2006},
month = {Mon May 15 00:00:00 EDT 2006}
}
  • We report here resonant x-ray scattering (RXS) experiments carried out at the Mn K edge in Bi1-xSrxMnO3 (x=0.3, 0.5) single-crystals at room temperature. These compounds show a so-called charge ordered (CO) state at room temperature. Strong resonances were observed as the photon energy is tuned through the Mn K-edge for several weak superstructure (h 0 0) and (0 k 0) and forbidden (h/2 0 0) and (0 k/2 0) reflections with h, k odd within the a-b plane (Ibmm setting) in the x=0.3 and x=0.5 compounds, respectively. The reported azimuth angle and polarization dependences of the resonant intensity for themore » complete set of reflections point out to a structural transition at TCO that stabilizes a checkerboard ordering of two non-equivalent Mn atoms with different local geometrical structures. We conclude that the checkerboard ordered phase is a common ground state in the so-called CO manganites, A1-xBxMnO3, independently of the nature of the A and B atoms and for compositions x even far from 0.5. Moreover, the quantitative analysis of the resonant reflections shows that the electronic states of the two non-equivalent Mn atoms are far from the ionic (+3 and +4) species.« less
  • Orbital and magnetic ordering in La{sub 0.5}Sr{sub 1.5}MnO{sub 4} have been studied with resonant soft x-ray scattering at the Mn L{sub 2,3} edges and for the first time azimuthal angle scans and polarization analysis are presented. The azimuthal angle dependencies are well described by the occurrence of a quadrupole (orbital) ordering below T{sub OO} and an additional dipole (magnetic) contribution below T{sub N}. There are no indications that there is an enhanced Jahn-Teller distortion at T{sub N} as reported in a previous study. Subsequently, it is shown that there is simultaneous ferro- and antiferromagnetic ordering along the c-direction.
  • We report resonant x-ray scattering data of the orbital and magnetic ordering at low temperatures at the Mn L{sub 2,3} edges in La{sub 0.5}Sr{sub 1.5}MnO{sub 4}. The orderings display complex energy features close to the Mn absorption edges. Systematic modeling with atomic multiplet crystal field calculations was used to extract meaningful information regarding the interplay of spin, orbital, and Jahn-Teller order. These calculations provide a good general agreement with the observed energy dependence of the scattered intensity for a dominant orbital ordering of the d{sub x{sup 2}}{sub -z{sup 2}}/d{sub y{sup 2}}{sub -z{sup 2}} type. In addition, the origins of variousmore » spectral features are identified. The temperature dependence of the orbital and magnetic ordering was measured and suggests a strong interplay between the magnetic and orbital order parameters.« less
  • No abstract prepared.
  • A resonant photoemission study has been performed for Pr{sub 1{minus}x}Sr{sub x}MnO{sub 3}thinsp(x=1/3,1/2) and the partial spectral weight (PSW) distributions of both Pr 4f and Mn 3d electrons have been determined. With varying temperature ({ital T}) and {ital x}, metal-insulator transitions are observed in the photoemission data. The Pr ions in Pr{sub 1{minus}x}Sr{sub x}MnO{sub 3} are trivalent, and Pr 4f PSW exhibits a dominant hybridization peak indicating large Pr 4f{minus}Othinsp2p mixing. The Mn 3d PSW at low {ital T} shows a charge gap for x=1/2, and a reduced spectral intensity near E{sub F} for x=1/3, suggesting the localized nature due tomore » the lattice polaron formation. thinsp {copyright} {ital 1999} {ital The American Physical Society}« less