• Journal of the Korean institute of surface engineering
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• v.44 no.6
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• pp.255-259
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• 2011

The thickness dependence of magnetic properties was experimentally investigated in nanocrystalline Fe-Hf-N thin films fabricated by a RF magnetron sputtering method. In order to investigate the thickness effect on their magnetic properties, the films are prepared with different thickness ranges from 90 nm to 330 nm. It was revealed that the coercivity of the thin film increased with film thickness. On the contrary, the saturation magnetization decreased with film thickness. On the basis of the SEM and TEM, an amorphous phase forms during initial growth stage and it changes to crystalline structure after heat treatment at $550^{\circ}C$. Nanocrystalline Fe-Hf-N particles are also generated.

• Journal of the Korean Magnetics Society
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• v.8 no.3
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• pp.138-143
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• 1998

We have investigated the magnetic properties of FeBN and FeSiN films deposited by RF magnetron reactive sputtering system. It was investigated that the compositions of B, Si and N were the main factors influencing the soft magnetic properties and film resistivity. The addition of small amount of N significantly improve the soft magnetic properties and electrical resistivity. The FeBN and FeSiN films were showed good soft magnetic properties which were Hc<1 Oe, Bs:19~19 kG and $\mu$'>1000 values. The composition of films were $Fe_{75}(BN)_{25},\;Fe_{78}(SiN)_{22}$ and resistivity was 100~120 $\mu$$\Omega$-cm. but, futher increase in B, Si and N concentration degraded the soft magnetic properties due to formation of nitride such as $Fe_4N$ compound.

• Journal of the Korean Magnetics Society
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• v.15 no.1
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• pp.17-20
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• 2005

The influence of $O_2$ partial pressure on saturation mgnetization, coercivity, anisotropy field and effective permeability (over 1GHz) of as-deposited Co-Fe-Al-O thin films, which were fabricated by RF magnetron reactive sputtering method, were investigated. The $Co_{69.9}Fe_{20.5}A_{14.4O_{5.2}$ thin film fabricated at $O_2$ partial pressure of 4% exhibits the best magnetic softness with saturation magnetization 4${$pi}$Ms of 18.1 kG, coercivity of 0.82 Oe, anisotropy field ($H_k$) of Oe, and effective permeability (${\mu}_{eff}$) about 1,024 above 1 GHz. the electrical resistivity of Co-Fe-Al-O thin films were increased with increasing $O_2$ partial pressure, the electrical resistivity of $Co_{69.9}Fe_{20.5}A_{14.4O_{5.2}$ thin film with the best soft magnetic properties was 560.7 ${\mu}{\Omega}$am. Therefore, It is assumed that the good soft magnetic properties of $Co_{69.9}Fe_{20.5}A_{14.4O_{5.2}$ thin film results from high electrical resistivity and large anisotropy field.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.339-341
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• 2007

Soft ferromagnetic materials are very useful for many sensors using magnetic materials with high permeability, low coercivity and low hysteresis loss. Among them, FeCoSiBNi amorphous magnetic films show us a good impedance change(about 3.05%/Oe, at 12MHz) by the exterior magnetic field in this experiment. These are produced by rapid solidification from the melt and the material is ejected in a jet from a nozzle and quenched in a stream of liquid. After that, we make them a shape of wire with different sizes of width. Thus, we can find that the impedance change (122.16%, at 12MHz) is occurred and the fabricated magnetic wire has the characteristics of good sensor element.

• Proceedings of the Korean Magnestics Society Conference
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• 1991.05a
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• pp.77-78
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• 1991

• Korean Journal of Materials Research
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• v.10 no.11
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• pp.755-759
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• 2000

The influence of $O_2$partial presure on saturation magnetization, coercivity and effective permeability(0.5~100MHz) of as-deposited Fe-Sm-O thin films, which were fabricated by RF magnetron reactive sputtering method, were investigated. The nanocrystalline Fe(sub)83.4Sm(sub)3.4O(sub)13.2 thin film fabricated at $O_2$partial pressure of 5% exhibits the best magnetic softness with saturation magnetization of 18kG, coercivity of 0.82 Oe and effective permeability about 2,600 at 0.5~100MHz. $\alpha$-Fe grain size is decreased with increasing $O_2$partial pressure. In case of $O_2$partial pressure of 10%, it is observed that FeO compound is formed and soft magnetic properties are decreased. The electrical resistivity of Fe-Sm-O thin films were increased with increasing $O_2$partial pressure, the electrical resistivity of Fe(sub)83.4Sm(sub)3.4O(sub)13.2 thin film with the best soft magnetic properties was 130 $\mu$$\Omega$cm. Therefore, It is assumed that the good soft magnetic properties of Fe(sub)83.4Sm(sub)3.4O(sub)13.2 thin film results from high electrical resistivity and decreasing $\alpha$-Fe grain size due to precipitation of Sm-Oxide phase.

• Journal of Magnetics
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• v.13 no.3
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• pp.92-96
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• 2008

There are few reports of high frequency loss behavior in the near-field for magnetic films with semiconducting properties, even though semiconducting magnetic materials, such as soft magnetic amorphous alloys and nanocrystalline thin films, have been demonstrated. The electromagnetic loss behavior of multilayer magnetic films with semiconducting properties on the microstrip line in quasi-microwave frequency band was analyzed numerically using a commercial finite-element based electromagnetic solver. The large increase in the absorption performance and broadband characteristics of the semiconducting/insulating layer magnetic films examined in this study were attributed to an increase in the loss factor of resistive loss. The electromagnetic reflection increased significantly with increasing conductivity, and the loss power deteriorated significantly. The numerical results of the magnetic field distribution showed that a strong radiated signal on the microstrip line was emitted with increasing conductivity and decreasing film thickness due to re-reflection of the radiated wave from the surface of the magnetic film, even though the emitted levels varied with film thickness.

• Current Applied Physics
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• v.18 no.11
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• pp.1185-1189
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• 2018

Thickness-dependent magnetic domain structure of ultrathin Co wedge films (0.3 nm-1.0 nm) sandwiched by Pt layers was investigated by scanning transmission x-ray microscopy (STXM) employing X-ray magnetic circular dichroism (XMCD), utilizing elliptically polarized soft x-rays and electromagnetic fields, with a spatial resolution of 50 nm. The magnetic domain images measured at the Co $L_3$ edge showed the evolution of the magnetic domain structures from maze-like form to the bubble-like form as the perpendicular magnetic field was applied. The asymmetric domain expansion of a 500 nm-scale bubble domain was also measured when the in-plane and perpendicular external magnetic field were applied simultaneously.

• Transactions on Electrical and Electronic Materials
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• v.7 no.1
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• pp.42-50
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• 2006

Co-Fe-Al-O nano-granular thin films with high electrical resistivity, fabricated by radio frequency magnetron sputtering under an $Ar+O_2$ atmosphere, are found to show good soft magnetic properties in the GHz frequency range. The real part value of the relative permeability is 260 at low frequencies and this value is maintained up to the GHz frequency range. A non-integrated type noise filter on a coplanar waveguide transmission line is demonstrated by using the Co-Fe-Al-O nano-granular thin film with the dimensions of $4\;mm(l){\times}4\;mm(w){\times}0.1\;{\mu}m(t)$. The insertion loss is very low being less than 0.3 dB and this low value is maintained up to 2 GHz. At a ferromagnetic resonance frequency of 3.3 GHz, the degree of noise suppression is measured to be 3 dB. This level of noise attenuation is small for real applications, but there is much room for further improvement by increasing the magnetic volume and integrating the magnetic thin film into the CPW transmission line.

• Journal of the Korean Magnetics Society
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• v.19 no.6
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• pp.197-202
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• 2009

The property of soft magnetism for the Corning glass/non-buffer or buffer Ta/Conetic(NiFeCuMo)/Ta prepared by the ion beam deposition sputtering was studied. The effect of crystal property and post annealing treatment depending on the thickness of Conetic thin films was investigated. The coercivities of Conetic thin films with easy and hard direction along to the applying magnetic field during deposition were compared with each other. The coercivity and magnetic susceptibility of Ta(5 nm)/Conetic(50 nm) thin film were 0.12 Oe and 1.2 ${\times}\;10^4$, respectively. From these results, firstly, the Conetic thin film was more soft magnetism thin film than other one such as permalloy NiFe. Secondly, the usage of soft magnetism Conetic thin film for GMR-SV (giant magneoresistance-spin valve) or MTJ (Megnetic Tunnel Junction) structure in a low magnetic field can be possible.