HOPPING CONDUCTION IN La1/2Ba1/2(Mn1-xAlx)O3

Abstract

Electrical resistivity behaviour of La_1/2Ba_1/2(Mn_1-xAl_x)O₃ compounds, prepared by the solid state reaction, have been investigated below the charge-ordering temperature to understand the mechanism of conduction. On analyzing the data by using several theoretical models, it is found that the metallic (ferromagnetic) part of the resistivity () (below T_P) fits well with the equation ρ = ρ₀ + ρ₂T², where ρ₀ is due to the importance of grain/domain boundary effects, a second term ~ρ₂T² appears that might be attributed to the electron–electron scattering. In high temperature (Tp<T<θ_D/2) paramagnetic insulating regime, the resistivity of samples obey the T^-1/4 law, characteristic of variable range hopping (VRH) model.