Effect of bismuth doping on the physical properties of La–Li–Mn–O manganite

The effects of bismuth doping at La site on magnetic, electrical and thermopower properties of LaLiMnO₃ manganites have been investigated. The substitution of Bi ion leads to the weakening of ferromagnetic ordering at low temperature, and Curie temperature (T _C) decreases with increase in Bi content. Interestingly, a dramatic increase in the magnitude of Seebeck coefficient at low temperature is observed in Bi-doped samples which might find potential application as thermoelectric. The results are attributed to the combined effect of the disorder and antiferromagnetic interaction induced by Bi doping. Both ρ(T) and S(T) data in the high-temperature region are discussed using small polaron hopping model.