Evidence of local lattice distortions in La1-xSrxMnO3 provided by pulsed neutron diffraction

The pulsed neutron powder diffraction study of La1-xSrxMnO3 reveals that the local atomic structure is significantly different from the long range structure, and these differences are important in understanding their properties. Even though the crystal structure suggests that the Jahn-Teller (JT) distortion disappears quickly with Sr doping, the analysis by the pair distribution function technique indicates that locally JT distortions are always present. Doped charge carriers induce local anti-JT distortions and disrupt the long range JT distortion. In the paramagnetic phase, such anti-JT distortions are represented by Mn4+ ions, corresponding to small polarons. Below T-c charge carriers are delocalized, but still induce local lattice distortions, giving rise to an inhomogeneous metallic state. The effects of these local distortions are discussed. (C) 1997 American Institute of Physics.