Electrical resistivity in carrier-doped RNb 3 O 9 (R=La, Ce, Pr and Nd)

摘要: Abstract Carrier doping in insulating compounds RNb3O9 (R=La, Ce, Pr and Nd) has been carried out. Electrical resistivities below 300 K were measured for excess R-doped compounds; R1+xNb3O9 (x≤0.2) oxygen-deficient RNb3O9−y (y=0.1). All the samples showed dc conductivity, however very high, e.g. even lowest value at is about 1 Ω cm CeNb3O8.9. The of RNb3O8.9 varied with temperature holding relation ln ρ∝(T 0 /T) 1/4 indicating Mott variable-range hopping (VRH) conductivity. In both systems, Ce-containing show much lower resistivities. It noteworthy that resistivity CeNb3O8.9 than values other RNb3O8.9, two orders magnitude 300 K.