Electrical Transport Properties in Ta-Doped SnO₂ Thin Films

Abstract

The structure, carrier concentration and low temperature magnetoresistance of Tantalum-doped Tin oxide thin films prepared by RF magnetron sputtering method have been investigated. Hall coefficient is negative at all measuring temperatures, which confirms the n-type characteristic of the films with metallic characteristic. The low temperature magnetoresistance measurement show negative magnetoresistance at all measured temperatures from 2 to 30 K. However, weak-localization theories can not explain the behavior of the negative magnetoresistance of our samples. We fitted the magnetoresistance data of the samples with semiempirical expression that takes into account the third order sd exchange Hamiltonians. The theory and experiment are in excellent agreement. This strongly suggests that the magnetoresistance in SnO2: Ta film originates from the scattering of conduction electrons due to localized magnetic moments.