In order to understand the electric current distribution in a non-local geometry, the geometrical dependence of non-local Hall resistance was investigated for lateral devices consisting of an FePt perpendicular spin polarizer and a Au Hall cross. The finite element simulation was also carried out to calculate the electric potential in the devices. The experiment and the simulation indicated that non-local Hall resistance included the contribution of anomalous Hall effect (AHE) in the FePt perpendicular spin polarizer. The resistance change due to AHE in FePt became remarkable for devices with a wide electrode. Taking into account the contribution of AHE, the spin Hall angle was estimated to be 0.05 for the device with a narrow Au electrode.

The effect of wet chemical treatment on the magnetic tunneling junction (MTJ) was examined. The tunneling magneto-resistance (TMR) increased and the resistance of anti-parallel state and parallel state decreased when a wet cleaning treatment was carried out after a reactive ion etching process. Furthermore, the exfoliation between the capping layer and Inter layer Dielectric (ILD) was prevented. Presumably, these were due to the elimination of the damaged layer and the residues. This investigation showed that the wet treatment after the MTJ patterning using RIE process could improve the MTJ properties without degradation of Hc, such as TMR and Rlow.

CoxC1-x granular films were deposited on Si substrates by a co-sputtering method. A large negative MR of 30.3% was obtained at 2 K for the sample prepared with the sputtering power of 50 W (C) and 4 W (Co). We have studied structural properties of Co-C granular films by Raman spectroscopy. Two peaks (D and G modes) from carbon bonds were clearly observed, and the intensity ratio of two peaks changed with the sputtering power, suggesting that the graphitization was promoted with the sputtering power. It was also revealed that the transport mechanism changed from tunneling to Mott’s variable range hopping and MR decreased with the sputtering power.