Separating the causes of orbital ordering inLaSr2Mn2O7 using resonant soft x-ray diffraction

Abstract

Resonant soft x-ray diffraction has been used to probe the temperature dependent orbital and magneticstructure of LaSr2Mn2O7. Previous crystallographic studies have shown that this material has almost noMnO6 oxygen displacements due to Jahn–Teller distortions at low temperatures. Within thelow-temperature A-type antiferromagnetic phase, we found strong intensity at the () orbital and (0, 0, 1) magnetic reflections. This shows that even in the near absence ofJahn–Teller distortions, this compound is strongly orbitally ordered. A fit to the MnL-edge resonance spectra demonstrates the presence of orbital ordering of theMn3+ ions with virtually no Jahn–Teller crystal field in addition to possibleMn3+ and Mn2+-like valence fluctuations.