• Journal of the Korean Magnetics Society
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• v.10 no.6
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• pp.280-294
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• 2000

[(300nm)Ta/(500nm)NdFeB/(300nm)Ta] thin films were deposited at 5 mTorr Ag gas pressure by RF-DC magnetron sputtering, and their magnetic properties were investigated. The [Ta/NdFeB/Ta] films deposited on heated Si substrates showed high perpendicular anisotropy and excellent hard magnetic properties. The films sputtered at tile substrate temperature of T$\sub$s/=650$^{\circ}C$ and 700$^{\circ}C$ showed (BH)$\sub$max/=20 MGOe and $\sub$i/H$\sub$c/= 18.9 kOe along the perpendicular direction to the film plane, respectively.

• Journal of Surface Science and Engineering
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• v.19 no.4
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• pp.140-148
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• 1986

Using sodium pyrophoshate as complexing agent, the characteristics and the magnetic properties of the films deposited from electroless cobalt plating bath have been studied. The result obtained are as following; 1. It was found that the optimum bath compositions consisted of 0.1M cobalt sulfate, 0.2M sodium hypophosphite as reducing agent, 0.4M sodium pyrophosphate as complexing agent and 0.5M ammonium sulfate as buffer agent, whereas good operating conditions were the bath of pH 10.5 adjusted with ammonia and 70$^{\circ}C$ of bath temperature, respectively. 2. The coercive force and the squareness of magnetic films were increased with deposition from the low temperature bath. 3. The phosphorous content in Co-P films deposited from these bath was relatively higher than that from Brenner bath. It was assumed to be due to codeposition of phosphorous from the pyrophosphate anion in the solution.

• Journal of Magnetics
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• v.12 no.3
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• pp.129-132
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• 2007

Bismuth-substituted yttrium iron garnet (Bi:YIG, $Bi_{0.5}Y_{2.5}Fe_5O_{12}$) films were deposited with aerosol deposition method and their magnetic and optical properties were investigated as a function of annealing temperature. Since the ceramic films deposited with aerosol deposition method have not a perfect crystal structure due to non-uniform internal stress occurred by mechanical collision during their deposition, the post annealing could be a key process to release its internal stress and to improve its micro structure for optimizing the magnetic and magneto-optic properties of films. The crystallinity of Bi: YIG film was improved with increase of annealing temperature, and the saturation magnetization increased up to 87 emu/cc at $800^{\circ}C$. The Faraday rotation increased up to $1.4deg/{\mu}m$ by annealing at $700^{\circ}C$ around the wavelength of $0.5{\mu}m$. The optical transmittance of the Bi:YIG film was also improved in visible region.

• Journal of Magnetics
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• v.7 no.4
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• pp.151-155
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• 2002

In situ stress changes at interfaces of ultrathin magnetic films were measured by means of a non-contact optical fiber bundle displacement detector. A bending of the substrate due to stress of a deposited film was detected in cantilever geometry. The highest sensitivity of 134 mV/$\mu$m for the displacement detector was realized with a help of computer simulation. The detector was applied to in situ stress measurements of Co/Pt and Ni/Pd magnetic multilayer films prepared on the glass substrates by dc magnetron sputtering. The detector turned out to have a submonolayer sensitivity that enables to observe coherent-to-incoherent transition in these mismatched multilayers and even detect the stress changes within the monoatomic coverage. This highly sensitive detector paves new way to probe the stress relaxation at an interface in ultrathin films.

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.36.1-36.1
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• 2008

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.302.2-302.2
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• 2008

• Journal of the Korean Magnetics Society
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• v.4 no.3
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• pp.263-271
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• 1994

We have produced $Co_{1-x}Pt_{x}(X\;=\;0.53\;and\;0.75)$ alloy films by DC magnetron sputtering at various substrate temperatures and sputtering pressures. Sputter-deposited Co-Pt alloy films showed a strong (111) texture, and the degree of (111) texture of the as-deposited film was found to depend on the substrate temperature and Ar pressure. However, we observed that the degree of (111) texture did not affect the magnetic properties. In addition, we have investigated the effect of heat-treatment on magnetic properties of these films. While the magnetic properties of the $Co_{0.25}Pt_{0.75}$ alloy films showed no noticeable changes, the coercivities and the squarenesses of the $Co_{0.47}Pt_{0.53}$ alloy films were drastically increased by annealing. Structural analysis using transmission electron microscopy(TEM) and x-ray diffractornetry(XRD) revealed that $CoPt(L1_{0})$ and $CoPt_3(L1_{2})$ ordered phases, respectively, were formed, each with a strong (111) texture. By comparing the magnetic properties between $CoPt(L1_{0})$ and $CoPt_3(L1_{2})$ ordered phases in relation to the atomic arrangements in a unit cell, we conclude that the magnetic anisotropy in the Co-Pt alloy system depends mainly on the atomic arrangements of Co and Pt.

• Journal of Magnetics
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• v.11 no.1
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• pp.8-11
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• 2006

Recently half-metallic full-Heusler alloy films have attracted significant interests for spintronics devices. As these alloys have been known to have a high spin polarization, very large TMR ratio is expected in magnetic tunnel junctions. Among these alloys, $Co_2MnSi$ full-Heusler alloy with a high spin polarization and a high Curie temperature is considered a good candidate as an electrode material for spintronic devices. In this study, the magnetic and structural properties of $Co_2MnSi$ Heusler alloy films were investigated. TMR characteristics of magnetic tunnel junctions with a $Co_2MnSi/SiO_2/CoFe$ structure were studied. A maximum MR ratio of 39% with $SiO_2$ substrates and 27% with MgO(100) substrates were obtained. The lower MR ratio than expectation is considered due to off-stoichiometry and atomic disorder of $Co_2MnSi$ electrode together with oxidation of the electrode layer.

• Journal of Magnetics
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• v.11 no.4
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• pp.167-169
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• 2006

Nanocrystalline CoFeHfO thin films have been fabricated by RF sputtering method. It is shown that the CoFeHfO thin films possess not only high electrical resistivity but also large saturation magnetization and anisotropy field. Among the composition investigated, $Co_{53}FE_{22}Hf_{10}O_{15}$ thin film is observed to exhibit good soft magnetic properties: coercivity ($H_{c}$) of 0.18 Oe; anisotropy fild ($H_{k}$) of 49.92 Oe; saturation magnetization ($4{\Pi}M_{s}$) of 15.5 kG. The frequency response of permeability of the film is excellent. The excellent magnetic properties of this film in addition of an extremely high electrical resistivity (r) of $185\;{\mu}cm$ make it ideal for uses in high-frequency applications of micromagnetic devices. It is the formation of a peculiar microstructure that resulted in the superior properties of this film.

• Journal of Magnetics
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• v.19 no.2
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• pp.121-125
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• 2014

$CoFe_2O_4(CFO)/BaTiO_3(BTO)/CoFe_2O_4(CFO)$ multilayered thin films were deposited on $Pt/TiO_2/SiO_2/Si$ substrates by the pulsed laser deposition (PLD) system with KrF excimer laser (${\lambda}=248nm$). BTO, CFO, BTO/CFO and CFO/BTO/CFO structured thin films were prepared and their crystal structures and microstructures, as well as their magnetic and magneto-electrical properties, were studied. The C-V characteristics of these multilayered thin films with different capacitor structures were obtained to confirm the change in their capacitances under a magnetic field. Finally, the capacitance of the CFO/BTO/CFO thin film as a function of bias voltage under an in-plane magnetic field of 1,000 Oe increased to 951.04 pF at 1 MHz, from 831.90 pF measured under no magnetic field, indicating 14.3% increase in magnetocapacitance.