Perpendicular magnetic anisotropy in CoSiB/Pd multilayers with various thicknesses

Abstract

In this letter, we report the perpendicular magnetic anisotropy of [CoSiB t(CoSiB) nm/Pd 1.3 nm](5) multilayer for t(CoSiB) equal to 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6 nm and of [CoSiB 0.3 nm/Pd t(Pd) nm](5) multilayer for t(Pd) equal to 1.1, 1.2, 1.3, 1.4, 1.5, and 1.6 nm. We also presented to for [CoSiB 0.3 nm/Pd 1.3 nm] (n) multilayer for n equal to 3, 5, 7, 9, 11 and 13. The coercivity (H (c) ) and the saturation magnetization (M (s) ) of the amorphous ferromagnetic material Co75Si15B10 were taken to be 1.6 Oe and 407 emu/cm(3), respectively. The H (c) in [CoSiB t(CoSiB) nm/Pd 1.3 nm](5) multilayers increased with increasing t(CoSiB) to reach a maximum at t(CoSiB) = 0.3 nm and then decreased for t(CoSiB) > 0.3 nm. The highest H (c) of 0.26 k Oe was obtained in [CoSiB 0.3 nm/Pd 1.3 nm](5) whereas the lowest Ms of 0.26 emu/cm(3) was obtained in the [CoSiB 0.3 nm/Pd 1.3 nm](3) multilayer. Additional Pd layers did not contribute to the perpendicular magnetic anisotropy. The single-domain structure evolved into a striped multi-domain structure as the bilayer repetition number n was increased above 7 after which (n > 7) the hysteresis had a bow-tie shapes.