Magnetoresistance of metallic perovskite oxide LaNiO 3−δ
Abstract
We report a study of the magnetoresistance (MR) of the metallic perovskite oxide LaNiO
3−δ
as a function of the oxygen stoichiometry
δ
(
δ≤
0.14), magnetic field (H
≤6T
) and temperature (1.5K
≤
T
≤
25K). We find a strong dependence of the nature of MR on the oxygen stoichiometry. The MR at low temperatures change from positive to negative as the sample becomes more oxygen deficient (i.e,
δ
increases). Some of the samples which are more resistive, show a resistivity minima at
T
min
≈
20K. We find that in these samples the MR is positive at T >
T
min
and negative for T <
T
min
. We conclude that in the absence of strong magnetic interaction, the negative MR in these oxides can arise from weak localisation effects.