Structural, magnetic and electronic properties on the Li-doped manganites

We present results of a comprehensive investigation of the structural, frequency dependent ac susceptibility, dc magnetization, magnetoresistance and thermoelectric power measurements on polycrystalline samples of La_1−xLi_xMnO₃ (0.05≤x≤0.30). All samples undergo ferromagnetic to paramagnetic transition and metal to semiconductor transition. A cusp in the zero field-cooled in dc magnetization and a frequency-dependent peak in the ac susceptibility reveal the glassy behaviors. The out of phase component of the ac susceptibility shows frequency-dependent peaks below the Curie temperature (indicative of glassy behavior) which have previously been interpreted in terms of freezing of clusters. The grain boundaries play a dominant role in the conduction process. The framework of the magnon and phonon drag concept analyzed thermoelectric power data at low temperature, while small polaron conduction mechanism explained thermoelectric power data at high temperature. It has been found that the percolation threshold sample is x=0.10, so the author's point of view refers to make spot on this sample in the future works. - Highlights: • The investigated samples undergo FM to PM and metal to semiconductor transition. • The M(T)_ZFC and χ(T)_ZFC measurements reveal that the glassy behaviors. • The χ''(T)_ZFC shows dependent peak where interpreted in the cluster freeze. • The TEP data analyzed in the magnon and phonon drag, and small polaron mechanism