Nanoscale Magnetism and Transport

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The investigation of the stacking structure and the fabrication process of tunnel junctions were carried out. The tunnel magnetoresistance (TMR) ratio and the resistance obtained were 49%, 3 kΩμmィイD12ィエD1 and 30%, 300ΩμmィイD12ィエD1. These results contribute to the application of TMR effect on magnetic random access memories (MRAM) and magnetic reading heads. Also, the analysis method of TMR junctions by local transport properties using conductive atomic force microscope (AFM) was established. (Miyazaki)In order to investigate the local magnetization of magnetic wires microfabricated, the simultaneous measurement of a resistance and a transverse voltage at several points was found to be effective. Most of anomalous behaviors reported were explained by anisotropic magnetoresistance with the continuous or discontinuous rotation of local magnetizations. Also, anomalous temperature dependence of a resistance for a bulk ferromagnet was found. (Sato)The Coulomb staircase caused by single electr … More on tunneling was observed for metal-nonmetal granular thin films. using by scanning tunneling microscope (STM) at room temperature. And also, the negative resistance which was. observed at the same period of the Coulomb staircase was found. This was suggested to be occurred by the spin accumulation effect. (Takanashi)In ferromagnet/superconductor/ferromagnet double junctions, spins were accumulated into the superconductor at the magnetizations of both ferromagnets aligned antiparallel, so that the super-conducting state was found to be controlled by applying voltages. This must be the new concept of the interaction between magnetism and superconducting effect. (Maekawa)The sharp interface of Fe/Cr was fabricated successfully by controlling the atomic order growth using Pb surfactant. The giant magnetoresistance (GMR) of Fe/Cr metallic multilayers with Pb surfactant was two times larger than that without Pb surfactant. This result showed experimentally that the interface structure was an important factor for the magnitude of GMR ratio and that the spin dependent scattering at the interface was a main origin of GMR (Yamamoto)In order to obtain the spin polarization of ferromagnets, magneto Coulomb oscillation phenomenon of a ferromagnetic single electron transistor (SET) was used. The polarity of spin polarization of Ni obtained for Al/Ni/Al-SET was negative, which corresponded to the result form band calculations. However, the absolute value was too small. Less