MAGNETISM AND MAGNETIZATION STRUCTURE OF C-AXIS ORIENTED SINGLE-CRYSTAL COBALT FILMS GROWN EPITAXIALLY ON RIGID UNDERLAYERS

c-axis oriented, single-crystal, Co films were grown on mica using either Ti or Ru underlayers and exhibited the following crystallographic orientation relationship (00.1)mica \\ (00.1)underlayer \\ (00.1)Co, and [11.0]mica \\ [10.0]underlayer \\ [10.0]Co. Fundamental magnetic properties of the films were measured: H(c) approximately 4 Ka/m, B(s) approximately 1.95 T, and K(u) approximately 5 X 10(5) J/m3 . The as-grown magnetization structure of thinner (t less-than-or-equal-to 30 nm) films shows mainly 180-degrees domain walls with a uniform distribution of crossties, while thicker (t=60 nm) samples show stripe domains with a width of 75 nm. In spite of their excellent c-axis orientation (FWHM(Co(002)) approximately 1.5-degrees), the effective anisotropy of these films is in-plane but with a small perpendicular magnetization component. These features in the hysteresis behavior are consistent with a simple noninteracting particle model incorporating the shape anisotropy of the small sized grains. For thinner samples the validity of this model has been verified by annealing experiments.