The effect of oxygen content on the atomic structure of ${\mathrm{La}}_{1-x}{\mathrm{Sr}}_x{\mathrm{MnO}}_{3+\delta }$ $\mathrm{}(x=0,0.04\mathrm{})\mathrm{}$ was studied by the pulsed neutron pair-density function technique. Excess oxygen $(\delta >0)$ in the system leads to vacancy formation at the cation sites and charge doping, resulting in changes in the average structure as well as transitions in the magnetic and transport properties. The most pronounced change in the local structure is the reduction in the magnitude of the local Jahn-Teller distortion around some manganese ions, in strong contrast to the case of divalent cation doping. Our result suggests an inhomogeneous charge distribution with possible localization at the defect site leading to relatively poor conductivity.

• Received 27 May 1998

DOI:https://doi.org/10.1103/PhysRevB.61.1351