Magnetic switching, relaxation, and domain structure of a Co/Si(111) film

• Published in: Journal of applied physics 1993-11, Vol.74 (9), p.5658-5665
• Main Authors: BAIRD, M. J, BLAND, J. A. C, GU, E, IVES, A. J. R, SCHUMANN, F. O, HUGHES, H. P
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Domain structure (including magnetic bubbles); Exact sciences and technology; Magnetic properties and materials; Magnetic properties of surface, thin films and multilayers; Magnetooptical effects; Metals and metallic alloys; Metals. Metallurgy; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Optical properties of specific thin films; Physics
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.354180

We have used scanning magneto-optic Kerr effect (MOKE) microscopy to investigate the magnetic relaxation of a polycrystalline hcp 125 Å Co/Si(111) film with planar uniaxial anisotropy, on time scales between 10 and 2400 s and with a spatial resolution of 15 μm. In a static magnetic field slightly less than the coercive field and applied along the easy axis direction, domains develop and the magnetization reversal proceeds via displacements of 180° domain walls. Microscopic images of this metastable state allow the 180° domains to be identified by calibration of the MOKE signal with respect to that for the saturated magnetization states. The 180° reversed domains are observed to grow in the direction of the field in the form of narrow fingers, extending via short Barkhausen jumps, randomly spaced in time over the entire time-scale range investigated, with typical distances between pinning sites of the order of microns. This reversal behavior is qualitatively similar to that reported for Au/Co perpendicular anisotropy films a few monolayers thick.