• Journal of the Korean Magnetics Society
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• v.20 no.4
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• pp.129-133
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• 2010

Two-layered ferromagnetic alloy films (NiFe, CoFe) with a Conetic (NiFeCuMo) intermediately soft magnetic layer of different thickness were investigated to correlate the coercivity values and magnetization process with the strength of saturation field of hard axis. Thickness dependence of the $H_{EC}$ (coercivity of easy axis), $H_{HS}$ (saturation field of hard axis.), and X (susceptibility) of NiFe and NiFeCuMo thin films for the glass/Ta(5 nm)/[CoFe or NiFe(5 nm-t/2)]/NiFeCuMo(t = 0, 4, 6, 8, 10 nm)/[CoFe or NiFe(5 nm-t/2)]/Ta(5 nm) films prepared by the ion beam deposition method was measured. The magnetic properties $H_{EC}$, $H_{HS}$, and X of two-layered ferromagnetic CoFe, NiFe films with a NiFeCuMo intermediately super-soft magnetic layer were strongly depended on the thickness of NiFeCuMo layer. The value of the coercivity and magnetic susceptibility of the NiFeCuMo film decreased by 25% and doubled relative to that of the NiFe film.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.8
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• pp.888-892
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• 2004

It is necessary to develop soft magnetic layer with high saturation magnetization 4 $\pi{M}_s$ and in-plane magnetic anisotropy field Hk for soft magnetic underlayer of perpendicular magnetic recording media with high signal to noise ratio. Fe-Co-B layer with high 4 $\pi$Ms of about 23 kG deposited on Ni-Fe and Ni-Fe/Si seedlayer exhibited very high in-plane magnetic anisotropy filed Hk of about 280 and 380 Oe, respectively, In-plane XRD studies clarified that the lattice spacing of planes along the easy axis direction was longer than that along the hard axis direction in the Fe-Co-B layers with high Hk. These results indicate that high Hk of Fe-Co-B/Ni-Fe and Fe-Co-B/［Ni-Fe/si］ layers were resulted from magnetoelastic anisotropy owing to a residual stress. Moreover, the high Hk in the Fe-Co-B/Ni-Fe layer was maintained until 30$0^{\circ}C$ annealing temperature.

• Journal of the Korean Ceramic Society
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• v.43 no.3 s.286
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• pp.143-147
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• 2006

Co-Fe-Al-O nanogranular thin films were fabricated by RF-magnetron sputtering under an $Ar+O_2$ atmosphere. High resolution transmission electron microscopy revealed that the Co-Fe-Al-O films are composed of bcc (Co, Fe) nanograins finer than 5 nm and an Al-O amorphous phase. A very large electrical resistivity of $374{\mu}{\Omega}cm$ was obtained, together with a large uniaxial anisotropy field of 50 Oe, a hard axis coercivity of 1.25 Oe, and a saturation magnetization of 12.9 kG. The actual part of the relative permeability was measured to be 260 at low frequencies and this value was maintained up to 1.3 GHz. The ferromagnetic resonance frequency was 2.24 GHz. The resulting Co-Fe-Al-O nanogranular thin films with a high electrical resistivity and high resonance frequency are considered to be suitable for GHz magnetic device applications.