Soft X-Ray Resonant Diffraction Study of Magnetic and Orbital Correlations in a Manganite Near Half Doping

Abstract

We have utilized resonant x-ray diffraction at the Mn $L_{II,III}$ edges in order to directly compare magnetic and orbital correlations in ${\mathrm{Pr}}_{0.6}{\mathrm{Ca}}_{0.4}{\mathrm{MnO}}_3$. Comparing the widths of the magnetic and orbital diffraction peaks, we find that the magnetic correlation length exceeds that of the orbital order by nearly a factor of 2. Furthermore, we observe a large ($\sim 3\mathrm{eV}$) spectral weight shift between the magnetic and orbital resonant line shapes, which cannot be explained within the classic Goodenough picture of a charge-ordered ground state. To explain the shift, we calculate the orbital and magnetic resonant diffraction line shapes based on a relaxed charge-ordered model.