Direct observation of oxygen superstructures in manganites

Stéphane Grenier (1) , K.J. Thomas (2) , J.P. Hill (2) , U. Staub (3) , Y. Bodenthin (3) , M. Garcia-Fernandez (3) , V. Scagnoli (4) , V. Kiryukhin (5) , S.-W. Cheong (5) , B.G. Kim (5) , Jean-Marc Tonnerre (6)

1 NEEL - MRS - Matériaux, Rayonnements, Structure
2 BNL - Brookhaven National Laboratory [Upton, NY]
3 PSI - Paul Scherrer Institute
4 ESRF - European Synchrotron Radiation Facility
5 RU - Rutgers, The State University of New Jersey [New Brunswick]
6 NEEL - SIN - Surfaces, Interfaces et Nanostructures

We report the observation of superstructures associated with the oxygen 2p-states in two prototypical manganites using x-ray diffraction at the oxygen K-edge. In the stripe order system Bi0.31 Ca0.69 MnO3 , hole-doped O states are orbitally ordered, at the same propagation vector as the Mn orbital ordering, but no oxygen charge stripes are found at this periodicity. In La 7/8 Sr 1/8 MnO3 , we observe a 2p charge ordering described by alternating hole-poor and hole-rich MnO planes that is consistent with some of the recent predictions.

Mots clés: resonant x-ray diffraction; manganite

Domaines: Electrons fortement corrélés [cond-mat.str-el]

Stéphane Grenier, K.J. Thomas, J.P. Hill, U. Staub, Y. Bodenthin, et al.. Direct observation of oxygen superstructures in manganites. Physical Review Letters, 2007, 99, pp.206403. ⟨10.1103/PhysRevLett.99.206403⟩. ⟨hal-00149105v2⟩