Electric-field-induced migration of oxygen ions in epitaxial metallic oxide films: Non-Debye relaxation and 1/f noise - art. no. 104304

We have investigated the. kinetics of current-induced change of resistance and conductivity noise in thin epitaxial metallic films of LaNiO3. The resi stance of the film changes at a very low current (threshold current density J(th)similar to 10(3) A/cm(2)). We find that the time dependence associate d with the change of resistance shows a stretched-exponential-type dependen ce at lower temperature. Above a certain temperature scale T* (approximate to 350 K), this crosses over to a creep-type behavior. At T similar toT*, t he time scale shows a drastic drop in the magnitude, and a long-range diffu sion sets in, which leads to an increase in the conductivity noise. The phe nomenon is like a "glass-transition" in the random lattice. of oxygen ions. We observe that the stretched exponential relaxation function, as obtained from time dependence of resistivity change, can explain the spectral struc ture as well as the temperature dependence of the low-frequency conductivit y noise. The frequency and temperature dependence of noise could clearly id entify the various processes, which had been seen in the current-stressing experiments carried out in the time domain. This establishes a quantitative link between the dynamics of current-induced resistivity changes and the c onductivity noise. Both the phenomena are direct consequences of the low-fr equency dynamics associated with the migration of the oxygen ions. Though d one in the specific context of oxide films (used in oxide electronics), thi s observation has a generic aspect, and the treatments developed here can b e used for establishing a quantitative link between electromigration curren t stressing and the conductivity noise in other metallic interconnects as w ell.