Giant magnetoresistance by using single layer graphene flake with chemical vapor deposition

In my thesis, spin transport through single layer graphene grown by chemical vapor deposition has measured in the local measurement configuration using aluminum oxide tunnel barriers and Co electrodes. Unlike the case of non-local measurements, we report positive magnetoresistance for graphene channels as long as 10 microns at room temperature. Our analysis shows that the spin diffusion length in graphene is 14 ±4 μm at room temperature, bringing us a step closer to spintronic applications based on graphene spin filters. In the next step, trying to transport spin filter up to 100 μm (between 10-200 μm). In this research, Single layer graphene layers have grown on 25-micron thick high purity Cu foils. Before loading the copper foils in the CVD furnace. Then the graphene layers have washed in new deionized water baths and then subsequently transferred to a Si/SiOx wafer piece using standard transfer methods. Spin filters have designed and fabricated using standard microlithography, sputter deposition and plasma etching techniques. Magneto transport measurements were perform on the fabricated samples at room temperature using four-terminal wiring, where 10 μA excitation current is use during measurements. A typical Magnetoresistance (MR) curve for a 10-micron graphene channel at room temperature. This result is interesting from the point of view that the MR measurements with graphene spin filters measured in the non-local geometry all show negative MR 14 while our results clearly and reproducibly show positive MR in the local measurement configuration in agreement with the researcher results.