Perpendicular Magnetic Anisotropy of CoSiB/Pt Multilayers

Abstract

We have investigated the perpendicular magnetic anisotropy of [CoSiB t(CoSiB)/Pt t(Pt)](n) multilayers as a function of the CoSiB and the Pt thicknesses and the number of repetition of the CoSiB/Pt bilayers. The coercivity (H(c)) and the saturation magnetization (M(s)) of the amorphous ferromagnetic material Co(75)Si(15)B(10) were taken to be 1.6 Oe and 407 emu/cm(3), respectively. The H(c) in [CoSiB t(CoSiB)/Pt 14 angstrom](5) multilayers increases with increasing t(CoSiB) to reach a maximum at t(CoSiB) = 3 angstrom and then decreases for t(CoSiB) > 3 angstrom. The highest H(c) of 224 Oe and the highest perpendicular magnetic anisotropy K(u) of 2 x 10(6) erg/cm(3) were obtained in the [CoSiB 3 angstrom/Pt 14 angstrom](5) multilayer. Additional Pt layers do not contribute to the perpendicular magnetic anisotropy. The single-domain structure evolves into a striped multidomain structure as the bilayer repetition number n increases above 6.