Influence of Al-doping on the structural, magnetic, and electrical properties of La0.8Ba0.2Mn1−x Al x O3 (0 ⩽ x ⩽ 0.25) manganites

Highlights: • The larger average grain size obtained due to aluminium doping and increasing annealing temperature. • Recently, the authors of Ref. [M.A.B. Narreto, H.S. Alagoz, J. Jeon, K.H. Chow, J. Jung, J. Appl. Phys. 115 (2014) 223905.], reported dynamics distortion and polaronic effects in the paramagnetic state of ${\text{La}}_{0.8}{\text{Ba}}_{0.2}{\mathrm{Mn}}_{1-x}{\mathrm{Al}}_x{O}_3$ manganites. Here we completed the phase diagram (Fig. 3 [1]) and point out of occurring spin-glass state in this manganite which is not intended for x = 0.15 doping. • The substitution of Al weakens the double exchange (DE) process. • We observed a Griffith's phase for some samples that annealed at 750°C and 1350°C. • The ρ(T) curve for the samples that shows metal-insulator transition was fitted with the percolation model. We have studied the effect of Al doping on structural, magnetic and electrical properties of ${\text{La}}_{0.8}{\text{Ba}}_{0.2}{\mathrm{Mn}}_{1-x}{\mathrm{Al}}_x{O}_3$ $(0⩽x⩽0.25)$ manganite annealed in 750° and 1350° temperatures. Results show $T_c$ 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 ${\mathrm{La}}_{0.8}{\mathrm{Ba}}_{0.2}{\mathrm{Mn}}_{1-x}{\mathrm{Al}}_x{O}_3$ manganites. Here we completed the phase diagram and show an occurrence of the spin-glass state in this manganite. The resistivity measurement shows, $T_{\mathrm{MIT}}$ (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.