Influence of Al-doping on the structural, magnetic, and electrical properties of La0.8Ba0.2Mn1−xAlxO3 (0 ⩽ x ⩽ 0.25) manganites

We have studied the effect of Al doping on structural, magnetic and electrical properties of La0.8Ba0.2Mn1-xAlxO3(0⩽x⩽0.25) manganite annealed in 750° and 1350° temperatures. Results show Tc decreases as Al ion substitution in Mn site. The magnetic susceptibility measurement shows Griffiths and spin-glass phase in aluminum-doped samples. Recently, Narreto et al., reported dynamic distortion and polaronic effects in the paramagnetic state of La0.8Ba0.2Mn1-xAlxO3 manganites. Here we completed the phase diagram and show an occurrence of the spin-glass state in this manganite. The resistivity measurement shows, TMIT (metal-insulator) transition temperatures decreases and the system become an insulator. The insulator-metal transition occurs for the undoped sample annealed at the low temperature in near 165 K, while this transition is weak for the undoped sample annealed at high temperature due to oxygen non-stoichiometry. Using three models VIZ., Adiabatic small polaron hoping, Variable range hopping, and Percolation model, the resistivity have been studied.