Efros-Shklovskii law and localized states in weakly doped lanthanum manganites

The existence of clusters in weakly doped lanthanum manganites at temperatures about twice as high as their Curie temperature T _C has been shown. Electrical resistance in weakly doped lanthanum manganites obeys the Efros-Shklovskii law. The temperature and magnetic-field dependences of a cluster size determined from the magnetotransport properties have been described using the model of phase separation into small metallic droplets within the dielectric paramagnetic and antiferromagnetic matrices. The results agree with the existence of the Griffiths phase.