• Electrical & Electronic Materials
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• v.10 no.10
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• pp.1016-1021
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• 1997

Magneto resistance properties in spin-valve sandwiches with various thickness of nanmagnetic layer in contact with the ferromagnetic NiFe film were investigated. The NiFe layer in contact with the NiO film was pinned by strongly exchange-biased coupling and the free NiFe layer at the film surface induced a sharp change in the magnetoresistance at -5~15Oe due to small coercivity. The NiO/NiFe/Cu/NiFe film showed a magnetoresistance ratio in the range of 2.3~2.9% and a field sensitivity above 2.2%/Oe with various of nonmagnetic layer. The NiO/NiFe/Cu/NiFe film of the field sensitivity above 2.2%/Oe suggests stang possibility of magnetic sensor matter.

• Journal of Magnetics
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• v.6 no.3
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• pp.83-85
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• 2001

The magnetoresistance properties of NiO/NiFe/Cu/NiFe spin valve film deposited on MgO(100) substrate with YBa$_2$$Cu_3O_7$(YBCO) film were investigated at room temperature and at 77 K. The magnetoresistance (MR) curves of the hybrid superconductor-magnetoresistor film structure showed an exchange coupling field of 300 Oe and an inverse magnetoresistance ratio of -6.5%. The magnetization configurations of the two magnetic layers in the NiO spin valve were antiparallel due to an increment in the conduction electron flow to superconductor YBCO film. This sample showed an inverse MR ratio.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.2
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• pp.138-143
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• 2003

A double spiral thin-film inductor with a NiFe magnetic core is integrated with DC-DC converter IC. The NiFe core is deposited on a polyimide film as the thinckness of NiFe is 2.5~3.5 ${\mu}$m. Then, copper conductor line is deposited on the NiFe core with double spiral structure. Process integration is performed by sequential processes of etching the polyimide film deposited both top and bottom of the NiFe core and electroplation copper conductor line from exposed metal pad of the DC-DC converter IC. Process integration is simplified by elimination planarization process for top core because the proposed thin-film inductor has a bottom NiFe core only. Inductor of the fabricated monolithic DC-DC converter IC is 0.53 ${\mu}$H when the area of converter IC and thin-film inductor are 5X5$\textrm{mm}^2$ and 3.5X2.5$\textrm{mm}^2$, respectively. The efficiency is 72% when input voltage and output voltage are 3.5 V and 6 V, respectively at the operation frequency of 8 MHz.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.366-366
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• 2010

Single crystalline Fe/NiO bilayers were epitaxially grown on Ag(001) and on MgO(001), and investigated by Low Energy Electron Diffraction (LEED), Magneto-Optic Kerr Effect (MOKE), and X-ray Magnetic Linear Dichorism (XMLD). We find that while the Fe film has an in-plane magnetization in both Fe/NiO/Ag(001) and Fe/NiO/MgO(001) systems, the NiO spins switch from out-of-plane direction in Fe/NiO/MgO(001) to in-plane direction in Fe/NiO/Ag(001). These two different NiO spin orientations generate remarkable different effects that the NiO induced magnetic anisotropy in the Fe film is much greater in Fe/NiO/Ag(001) than in Fe/NiO/MgO(001). XMLD measurement shows that the much greater magnetic anisotropy in Fe/NiO/Ag(001) is due to a 90o-coupling between the in-plane NiO spins and the in-plane Fe spins which causes a switching of the NiO spins during the Fe magnetization reversal.

• Journal of the Korean Magnetics Society
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• v.15 no.5
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• pp.265-269
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• 2005

Exchange bias effect of a various layered thin films were studied by FMR measurment. In plane angular dependence of a resonance field distribution which measured by FMR was analysed as a combined effect of an unidirectional anisotropy and an uniaxial anisotropy. Exchange biased NiFe/IrMn, IrMn/NiFe/IrMn, and NiFe/IrMn/CoFe thin films showed larger unidirectional anisotropy field and uniaxial anisotropy field with compared to that of an unbiased NiFe single thin film. In case of NiFe/Cu/IrMn, the film with thick Cu layer exhibited a similar trend to the unbiased NiFe thin film. NiFe/IrMn/CoFe thin film showed two resonance field distribution due to different ferromagnetic layers. In additon to the resonance field, the line width was also analysed with related to exchange bias effect.

• Journal of the Korean Magnetics Society
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• v.11 no.4
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• pp.163-167
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• 2001

The rotation of uniaxial anisotropy field of 700 ${\AA}$ thick sputtered NiFe thin film due to magnetic annealing was investigated. NiFe film was annealed in a magnetic field which is perpendicular to the initial induced uniaxial anisotropy field. The NiFe film becomes nearly isotropic after 1 hour annealing at 160 $^{\circ}C$. With increase of annealing temperature over 160 $^{\circ}C$, the film gets uniaxial anisotropy field again. An abrupt increase of H$\sub$c/ was observed with annealing temperature over 400 $^{\circ}C$. The X-ray diffraction analysis and Auger electron spectroscopy with Ar ion etching showed extensive grain growth in NiFe film with (111) texturing and interdiffusion with adjacent Au electrode layer by 400 $^{\circ}C$ magnetic annealing.

• Journal of the Korean institute of surface engineering
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• v.43 no.5
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• pp.243-247
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• 2010

The micro Vickers hardness and internal stress of Ni-Fe metal thin film synthesized by electrodeposition method at $25^{\circ}C$ were studied as a function of bath composition, and surface microstructure and atomic compositions of thin films were investigated by SEM and EDS. And the shape change of $200\;{\AA}$ Ni-Fe nanowires made using anodic aluminum oxide(AAO) templates by electrodeposition method were observed by SEM as a function of ultrasonic treatment time and bath composition. The Fe deposition contents on the substrate non-linearly increased with Fe ion concentration over total metal ion concentration. In case of low Fe contents film, the grain size is smaller and denser than high Fe contents deposited films, and the micro Vickers hardness increased with Fe contents of electrodeposited films. These results affected the shape change of nanowire after ultrasonic treatments.

• Journal of the Korean institute of surface engineering
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• v.44 no.4
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• pp.137-143
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• 2011

The internal stress and magnetic properties (coercivity and squareness) of Ni-Fe nano thin film synthesized by electrodeposition method were studied as a function of acidic chloride bath conditions (composition and temperature) and current density. Fe deposition patterns were different depending on the temperature of the solution, the stress of film decreased with increasing the solution temperature, and the depending on the amount of Fe deposition showed a parabolic shape. The grain size of film was inversely proportional to stress of thin film. The internal stress of thin film and magnetic properties were deeply relevant, and the stress of thin film had a relationship with bath conditions and grain size of the thin film surface.

• Journal of the Korean Magnetics Society
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• v.9 no.4
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• pp.196-202
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• 1999

The magnetic properties and the microstructures of the Mn-Ir/Ni-Fe multilayers with various stacking structures and buffer layer materials have been investigated. The (111) texture of Mn-Ir/Ni-Fe was observed in the top structures with Ta, Zr, or Ti buffer materials. However, all Mn-Ir/Ni-Fe multilayers with top structures exhibit high $H_{ex}$, regardless of the (111) preferred orientation of Mn-Ir film. The samples whose high $H_{ex}$ observed grain-to-grain epitaxial tendency and the large grain of Mn-Ir film at the interface. It can be explained that the $H_{ex}$ does not depend on the (111) texture of the Mn-Ir film and the interface roughness, but depends on the grain size of the Mn-Ir film and the morphology of the interface between the Mn-Ir and the Ni-Fe grains, and the $H_c$ depends on the interface roughness between the Mn-Ir and the Ni-Fe films.

• Korean Journal of Materials Research
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• v.28 no.10
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• pp.595-600
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• 2018

This study investigates the microstructural properties of CoCrFeMnNi high entropy alloy (HEA) oxynitride thin film. The HEA oxynitride thin film is grown by the magnetron sputtering method using nitrogen and oxygen gases. The grown CoCrFeMnNi HEA film shows a microstructure with nanocrystalline regions of 5~20 nm in the amorphous region, which is confirmed by high-resolution transmission electron microscopy (HR-TEM). From the TEM electron diffraction pattern analysis crystal structure is determined to be a face centered cubic (FCC) structure with a lattice constant of 0.491 nm, which is larger than that of CoCrFeMnNi HEA. The HEA oxynitride film shows a single phase in which constituting elements are distributed homogeneously as confirmed by element mapping using a Cs-corrected scanning TEM (STEM). Mechanical properties of the CoCrFeMnNi HEA oxynitride thin film are addressed by a nano indentation method, and a hardness of 8.13 GPa and a Young's modulus of 157.3 GPa are obtained. The observed high hardness value is thought to be the result of hardening due to the nanocrystalline microstructure.