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Orbital Bi-Stripes in High Doped Bilayer Manganites

T. A. W. Beale·P. D. Spencer·P. D. Hatton·S. B. Wilkins·M. von Zimmermann·S. D. Brown·D. Prabhakaran·A. T. Boothroyd
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Abstract

We present high resolution high energy and resonant x-ray diffraction results from La2-2xSr1+2xMn2O7 for x=0.55,0.575 and 0.60. These compounds show superlattice reflections at wavevectors of (h+-δ,k+-δ,l) and (h+-2δ,k+-2δ,l), arising from orbital ordering with associated Jahn-Teller distortions and charge ordering respectively. We observe a phase transition between the x=0.55 and x=0.575 doping levels. Samples with x=0.55 display structural characteristics similar to those previously reported for x=0.5. Compared to this, the long range order in samples with x=0.55 and x=0.6 have a distinct change in wavevector and correlation. We attribute this to a new orbital bi-stripe phase, accompanied by weak, frustrated, charge ordering. The observed azimuthal dependence of the orbital order reflections supports the model proposed for this new phase.

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T. A. W. Beale, P. D. Spencer, P. D. Hatton, S. B. Wilkins, M. von Zimmermann, S. D. Brown, D. Prabhakaran, A. T. Boothroyd. 2004-12-16. Orbital Bi-Stripes in High Doped Bilayer Manganites. https://doi.org/10.1103/physrevb.72.064432

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