Spin-state polaron in lightly hole-doped LaCoO_3
  Inelastic neutron scattering (INS), electron spin (ESR) and nuclear magnetic resonance (NMR) measurements were employed to establish the origin of the strong magnetic signal in lightly hole-doped La_{1-x}Sr_xCoO_3, x=0.002. Both, INS and ESR low temperature spectra show intense excitations with large effective g-factors ~10-18. NMR data indicate the creation of extended magnetic clusters. From the Q-dependence of the INS magnetic intensity we conclude that the observed anomalies are caused by the formation of octahedrally shaped spin-state polarons comprising seven Co ions. 
A. Podlesnyak, M. Russina, A. Furrer, A. Alfonsov, E. Vavilova, V.   Kataev, B. B\"uchner, Th. Str\"assle, E. Pomjakushina, ...