Local Structural Distortions Inducing Resonant Forbidden Reflections in LaMnO3

G. Subías (1) , J. Herrero-Martín (1) , J. García (1) , J. Blasco (1) , M. C. Sánchez (1) , C. Mazzoli (2) , Sergio Di Matteo (3) , K. Hatada (1, 3) , C. R. Natoli (3)

1 ICMA-CSIC - Instituto de Ciencia de Materiales de Aragón [Saragoza, España]
2 ESRF - European Synchrotron Radiation Facility
3 LNF - Laboratori Nazionali di Frascati = National Laboratory of Frascati

We have performed a complete resonant x-ray scattering (RXS) study at the Mn K- edge of LaMnO3. (h 0 0), (0 k 0) and (0 0 1) reflections with h, k and 1=odd, were measured between 10 and 300 K. We observed strong resonant peaks at the three types of reflections. They exhibit dipolar character with a change of the light polarization plane from σ to π. The azimuth angular dependence of all these reflections showed a characteristic sine evolution of π-period. The energy dependence of the scattered intensity for (h 0 0) and (0 k 0) reflections was identical while different structures were observed for the (0 0 1) reflections. We did not observe any change either on the resonance intensity or on the shape when crossing the Néel temperature TN~ 140 K. All resonances seem to be decoupled from the magnetic ordering and this is true even for (0 0 1) reflections, which correspond to the magnetic ordering direction. The tensor analysis indicates that the azimuth behavior of these reflections is reproduced by considering the crystallographic octahedral tilts.

Mots clés: X-ray scattering; Optical constants

Domaines: Biophysique [physics.bio-ph]

G. Subías, J. Herrero-Martín, J. García, J. Blasco, M. C. Sánchez, et al.. Local Structural Distortions Inducing Resonant Forbidden Reflections in LaMnO3. AIP Conference Proceedings, 2007, 882, pp.544-546. ⟨10.1063/1.2644587⟩. ⟨hal-00905341⟩