Electrical current influence on resistance and localization length of a Co–Al2O3 granular thin film

Towards the Universal Transport Properties of Metal/Insulator Granular Thin Films in the Low-Field Regime with Increasing Bias Potential or Current

“…The Co atoms formed grains with 16 Å mean diameter, showing a closedpacked hexagonal atomic structure. This sample presented superparamagnetism and tunnel magnetoresistance indicating the non-percolation of sample [13].…”

“…In the case of the Ti-SiO 2 film, this also allowed Scanning Transmission Electron Microscopy (STEM). The characterization of the Fe and Co granular in alumina had been reported before [12,13] and will be summarized below.…”

“…Our group has previously reported effects that occur in Fe-Al 2 O 3 [11,12] and Co-Al 2 O 3 [13] granular thin films in the low field regime. In those samples, ferromagnetic granules were dispersed in an alumina matrix, and it was observed that the thermal behavior of the resistance fitted better and over a broader temperature range when the Mott-VRH with =1/4 was used, as compared to the fitting with =1/2 (TAH).…”

“…In those samples, ferromagnetic granules were dispersed in an alumina matrix, and it was observed that the thermal behavior of the resistance fitted better and over a broader temperature range when the Mott-VRH with =1/4 was used, as compared to the fitting with =1/2 (TAH). Additionally, it was observed that the electrical resistance decreased with increasing current (or potential) for Fe-Al 2 O 3 [12] and Co-Al 2 O 3 [13] samples.…”

“…Many research groups report on magneto transport and electrical properties in metal/insulator granular [14][15][16][17][18][19], but the systematic analysis of the modifications of electrical properties with the change of bias/current is not common [11][12][13].…”