Magnetotransport and Dielectric Properties of Bi-Containing La0.6Sr0.15Bi0.15Mn1.1-xBxO3-δ Rare-Earth Manganites with B = Cr, Fe, Co, Ni

The effect of the replacement of manganese by 3d-ions of transition metals on the structural, microstructural, dielectric, and magnetotransport properties of nonstoichiometric La0.6Sr0.15Bi0.15Mn1.1-xBxO3-delta compositions with B = Cr, Fe, Co and Ni (0 <= x <= 0.3) was investigated. It is shown that in all compositions a weak change for the lattice parameter of the rhombohedral perovskite structure is observed. It is established that the real structure is defective and contains cationic V-(c) and anionic V-(a) vacancies. With increasing x, an increase in the resistivity and the absence of a metal-semiconductor phase transition for x > 0.20 are observed. The electron-phonon interaction constant gamma(ph) was determined. The most significant change in the structural and functional properties was observed for the compositions with B = Fe, for which constant gamma(ph) approximate to 7.7 achieves a maximum value. At x = 0.05, an increase in magnetoresistance effect of the tunnel type is observed.