Zn doping of La0.91Mn0.95O3 polycrystalline manganite:: transition from metallic-to insulating-like ferromagnetic ground state

The influence of substitution La3+ for Zn2+ on the conductivity of parent self-doped La0.9Mn0.95O3 manganite is studied. Such substitution leads to a sharp decrease of the Curie point (T-C) and induces smearing and disappearing of the metal-semiconductor transition in the vicinity of T-C with increasing of Zn concentration. A conductivity of Zn-doped La0.9Mn0.95O3 is described by variable-range hopping mechanism within a wide range of temperatures. Above results are discussed in the frame of the model taking into account the change of the band structure due to structural and magnetic disorders induced by Zn impurities in parent compound. (C) 2003 Elsevier B.V. All rights reserved.