Anomalous thermopower in bismuth doped La–Li–Mn–O manganite

• Bi doped LaLiMnO3 manganites were synthesized using wet chemical method.
• The Bi doped sample exhibits a huge thermopower of 0.9 V/K at ∼40 K.
• These huge values might find applications in thermoelectric devices.

Two polycrystalline samples, La5/6Li1/6MnO3 and La2/3Bi1/6Li1/6MnO3 having the same Mn3+/Mn4+ ratio were synthesized by the wet chemical method. After characterizing the samples by X-ray powder diffraction studies, dc magnetization, electrical resistivity and thermopower measurements were also carried out. It has been found that bismuth doped sample exhibits huge thermopower of 0.9 V/K in the low temperature region. The observed anomalous behavior is explained on the basis of the coexistence of antiferromagnetic phase in ferromagnetic matrix. The huge thermopower exhibited by these samples might find applications in thermoelectric devices.