The atomic pair-density function of ${\mathrm{La}}_{1-x}{\mathrm{Sr}}_x{\mathrm{MnO}}_3$ $(0\mathrm{}<~x<~0.4)$ obtained by pulsed neutron diffraction indicates that their local atomic structure significantly deviates from the average structure, and that the local Jahn-Teller (JT) distortion persists even when the crystallographic structure shows no JT distortion. In the paramagnetic insulating phase doped holes form one-site small polarons, represented by the local absence of JT distortion. The polarons become more extended at low temperatures, but local distortions are found even in the metallic phase. The role of polarons in the phase transitions in transport and magnetic properties are discussed.

• Received 18 July 1997

DOI:https://doi.org/10.1103/PhysRevB.56.R8475