We report direct observation of current-driven magnetic domain wall (DW) displacement by using a well-defined single DW in a microfabricated magnetic wire with submicron width. Magnetic force microscopy visualizes that a single DW introduced in a wire is displaced back and forth by positive and negative pulsed current, respectively. The direct observation gives quantitative information on the DW displacement as a function of the intensity and the duration of the pulsed current. The result is discussed in terms of the spin-transfer mechanism.

It was found that high current density needed for the current-driven domain wall motion results in the Joule heating of the sample. The sample temperature, when the current-driven domain wall motion occurred, was estimated by measuring the sample resistance during the application of a pulsed-current. The sample temperature was 750 K for the threshold current density of 6.7 x 10^11 A/m2 in a 10 nm-thick Ni81Fe19 wire with a width of 240 nm. The temperature was raised to 830 K for the current density of 7.5 x 10^11 A/m2, which is very close to the Curie temperature of bulk Ni81Fe19. When the current density exceeded 7.5 x 10^11 A/m2, an appearance of a multi-domain structure in the wire was observed by magnetic force microscopy, suggesting that the sample temperature exceeded the Curie temperature.Comment: 13 pages, 4 figure

We successfully designed Zn ion doped ZSM-5/silicalite-1 core-shell zeolite catalyst. On methanol to para-xylene (MTpX) over the core-shell catalyst, p-xylene yield was 40.7 C-mol% and para-selectivity (para-xylene selectivity in xylene isomers) was higher than 99 C-mol%, which substantially exceeds the other results reported in the literature.

A nanocontact structure (typically 22×34 nm2) between two NiFe wires was fabricated by an electron-beam lithography and a lift-off method, and the magnetoresistance was measured. The magnetization switching process was artificially controlled by engineering the sample geometry to realize a magnetic structure with a single domain wall (DW) trapped in the nanocontact area. This domain structure was confirmed by magnetic force microscopy observations. The magnetization rotation of 180° was realized within the nanocontact area. The contribution of the DW to the resistance was negative, which can be understood on the basis of anisotropic magnetoresistance.