Depression of positive magneto-conductance due to anti-weak localization effect in annealed In₂O₃-ZnO thick films

We investigated the magneto-conductivity Δ in three dimensional indium zinc oxide films with different resistivity ρ prepared by postannealing in air. The weak localization theory was fitted to data of Δ H) at temperatures below 50K by the use of suitable inelastic scattering time τ_i(T) and spin-orbit(S-O) scattering time τ_i. We found the ρ dependences of both times τ and τ_i in a range 1.5 × 10^-3Ω < ρ 300K) <4 × 10 ^-6Ω. As ρ increases, the ratio τ_i/τ increases from ≈ .005 to ≈ .5 and the Δ ^- at low temperatures changes from positive to negative values. We suggest a picture that the annealing in air brings the change of the S-O scattering from light to heavy atoms, namely, oxygen to indium and/or zinc atoms.