Transport and magnetic properties of metallic La1−xPbxNiO3−δ (0.0⩽x⩽0.1)

Abstract

Transport properties (resistivity and thermoelectric power) of Pb doped LaNiO3 viz. La1−xPbxNiO3−δ (0.0⩽x⩽0.1) show metallic behavior over a wide range of temperature (10–550K). Pb doping (up to 10%) at the La site does not destroy the metallic behavior of LaNiO3. The paramagnetic susceptibility χ decreases with Pb doping. Above 50K, χ is almost temperature independent and exhibits Pauli like features with a small additional Curie law contribution. The resistivity ρ increases with Pb doping though the thermoelectric power does not change proportionately, indicating that Pb doping does not introduce much disorder in the system. A linear T dependence of ρ observed above 150K suggests the importance of electron–phonon (el–ph) interactions but at temperature below 150K, ρ follows a T1.5 dependence. The estimated el–ph interaction constant λ increases (0.80–2.53) with Pb doping (x=0.0–0.1). No saturation of resistivity has been observed even up to 550K with x⩽0.1. The phonon frequency νph∼3444cm−1 of the undoped sample calculated from the absorption peak of the Fourier transform infrared spectra agrees well with that at ∼3025cm−1 estimated from the reported heat capacity data.