Investigation of Transport Properties and Dielectric Studies in La_(0.9)Bi_(0.1)MnO₃ Manganite

Low bismuth doping in lanthanum manganite is studied in detail for its unusual electrical conductivity and dielectric properties. The direct current electrical conductivity measurements exhibit proper semiconducting (or insulating) nature without any phase transitions. The low temperature direct current electrical conduction is due to the Mott-variable range hopping mechanism in the absence of the magnetic field (H = 0 T). However, in the presence of magnetic field (H = 8 T) the direct current electrical conduction switches to the Shklovskii–Efros-variable range hopping mechanism. The high-temperature direct current electrical conduction is governed by the Greaves-variable range hopping mechanism both at H=0 T and 8 T. The dielectric properties studied as a function of temperature and frequency exhibit a multiple relaxation process, which can be attributed due to the Debye + Maxwell–Wagner relaxation mechanisms. The frequency-dependent alternating current conductivity studied under constant temperatures further correlates with polaronic hopping transport mechanisms, as observed in direct current electrical conductivity measurements.