超微細構造磁性体およびその複合構造体の磁気・伝導特性

概要

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Micron-sized particulate arrays of amorphous R-Co (R = Sm and Gd) alloys and Fe_<20>Ni_<80> alloys with thicknesses of about 200nm were prepared on a 20-nm-thick niobium film by means of e-beam lithography and sputter deposition. The demagnetization curves of the arrays appeared different from those of bulk films with no pattern. When these arrays were illuminated with a laser beam, a set of Bragg reflections was observed. The obtained diffraction hysteresis loops were found to yield novel information about the domain structure on a sub-micron scale. Furthermore, interesting oscillations due to the fluxiod quantization were confirmed in the transition lines of the underlying Nb films. The super-conducting state of the Nb films was modulated by the stray fields of the square magnetic particles. Submicron-sized ferromagnetic Fe wires were also prepared, to investigate the pinning and depinning processes of 180o domain walls inside the wire. It was demonstrated by low-temperature transport and electron holography measurements that a clear change in resistivity appeared in association with depinning of a pinned single 180O domain wall.
社団法人日本磁気学会の論文
1997-03-01