2001/03/19 by M. v. Zimmermann, C. S. Nelson, Young‐June Kim +19 · 2 citations
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Magnetic and transport properties of perovskites and related materials #Rare-earth and actinide compounds #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.64.064411
24 pages, 8 figures
arxiv created 2001/03/19 · openalex publication_date 2001/07/19 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/30
We report an x-ray-scattering study of octahedral tilt ordering in the manganite series Pr_1\ensuremath-xCaxMnO3 with x=0.4 and 0.25 and in LaMnO3. The sensitivity to tilt ordering is achieved by tuning the incident x-ray energy to the LI, LII, and LIII absorption edges of Pr and La, respectively. The resulting energy-dependent profiles are characterized by a dipole-resonant peak and higher-energy fine structure. The polarization dependence is predominantly \ensuremathσ to \ensuremathπ and the azimuthal dependence follows a sin-squared behavior. These results are similar to those obtained in recent x-ray-scattering studies of orbital ordering carried out in these same materials at the Mn K edge. They lead to a description of the cross section in terms of Templeton scattering in which the tilt ordering breaks the symmetry at the rare-earth site. The most interesting result of the present work is our observation that octahedral tilt ordering persists above the orbital ordering transition temperatures in all three samples. Indeed, we identify separate structural transitions which may be associated with the onset of orbital and tilt ordering, respectively, and characterize the loss of tilt ordering versus temperature in LaMnO3.