• Journal of Magnetics
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• v.5 no.2
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• pp.44-49
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• 2000

Computer simulation of sensing current effects on the magnetic and magnetoresistance properties of a crossed spin-valve head is carried out. The spin-valve head has the following layer structure: Ta (8.0 nm)/NiMn (25 nm)/NiFe (2.5 nm)/Cu (3.0 nm)/NiFe (5.5 nm)/Ta (3.0 nm), and it is 1500 nm long and 600 nm wide. Even with a high pinning field of 300 Oe and a high hard-biased field of 50 Oe, the ideal crossed spin-valve structure, which is essential to the symmetry of the output signal and hence high density recording, is not realized mainly due to large interlayer magnetostatic interactions. This problem is solved by applying a suitable magnitude of sensing currents along the length direction generating magnetic fields in the width direction. The ideal spin-valve head is expected to show good symmetry of the output signal. This has not been shown explicitly in the present simulation, however, The reason for this is possibly related to the simple assumption used in this calculation that each magnetic layer consists of a single domain.

• Journal of Surface Science and Engineering
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• v.48 no.1
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• pp.23-26
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• 2015

What causes the transformation of a solar cell is the behavior difference of thermal expansion occurred between the substrate and the layer of semiconductor used in the solar cell. Therefore, the substrate has to possess a behavior of thermal expansion that is similar with that of semiconductor layer. This study employed electroforming to manufacture Fe-Ni alloy materials of different compositions. To verify the result from a finite element analysis, a two-dimensional Mo substrate was calculated and its verification experiment was conducted. The absolute values from the finite element analysis of Mo/substrate structure and its verification experiment showed a difference. However, the size of residual stress of individual substrate compositions had a similar tendency. Two-dimensional CIGS/Mo/$SiO_2$/substrate was modeled. Looking into the residual stress of CIGS layer occurred while the temperature declined from $550^{\circ}C$ to room temperature, the smallest residual stress was found with the use of Fe-52 wt%Ni substrate material.

• Corrosion Science and Technology
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• v.23 no.1
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• pp.11-19
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• 2024

A Fe-Ni Bainitic steel as a weathering steel application was developed by combining its excellent mechanical properties and corrosion resistance in maritime environments. Nickel concentration (0.4-3 wt%) and inverted austempering multi-step (IAM) process were primary determinants of the microstructure of the Fe-Ni Bainitic steel. The initial austempering steel was performed at 300 ℃ for 600 seconds to obtain a partly bainitic transformation. The steel was heated again for 1800 s at 450 ℃. The microstructure was comprised of ferrite, a blocky martensite/austenite island, and a homogeneous lath-shape bainite structure with widths ranging from 4.67 to 6.89 ㎛. The maximum strength, 1480 MPa, was obtained with 3 wt% nickel. In this study, corrosion behavior was investigated utilizing potentiodynamic and electrochemical impedance spectroscopy (EIS) tests. A higher nickel content in Fe-Ni Bainitic steel refined the grain size, improved the bainite fraction, lowered the corrosion rate to 0.0257 mmpy, and increased the charge transfer of film resistance to 1369 Ω.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.51 no.2
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• pp.82-86
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• 2002

A series of $Ni_xZn_yFe_{3-x-y}O_4$ films were prepared by spin-spray ferrite plating on glass substrates from aqueous solution at $90[^{\circ}C]$. The magnetic properties in terms of contents of Ni and Zn in the plated films are presented. All the films are polycrystalline with spinel structure. At x+y=0.58, the film presents preferential orientation. As composition of y in the films increases grain size and void in the films increases, while saturation magnetization and coercive force of the films decrease.

• Journal of the Korean Magnetics Society
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• v.17 no.4
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• pp.156-161
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• 2007

To develop array magnetic sensors, specular-type giant magnetoresistive- spin valve (GMR-SV) film of Glass/Ta(5)MiFe(7)/IrMn(10)NiFe(5)/$O_2$/CoFe(5)/Cu(2.6)/CoFe(5)/$O_2$/NiFe(7)/Ta(5)(nm) was deposited by using a high-vacuum sputtering system. One of 15 way sensors in the area of $8{\times}8mm^2$ was Patterned a size of $20{\times}80{\mu}m^2$ in multilayer sample by Photo-lithography. All of 15 sensors with Cu electrodes were measured a uniform magnetic properties by 2-probe method. The highest magnetic sensitivity of MR and output voltage measured nearby an external magnetic field of 5 Oe were MS = 0.5%/Oe and ${\triangle}$V= 3.0 mV, respectively. An easy-axis of top-free layers of $CoFe/O_2/NiFe$ with shape anisotropy was perpendicular to one of bottom-pinned layers $IrMn/NiFe/O_2/CoFe$. When the sensing current increased from 1 mA to 10 mA, the output working voltage uniformly increased and the magnetic sensitivity was almost stable to use the nano-magnetic devices with good sensitive properties.

• Journal of Magnetics
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• v.2 no.2
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• pp.50-54
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• 1997

The vacuum-annealed Ni80Fe20/Ag discontinuous multilayers were found to show giant magnetoresistive behaviors comparable to those of corresponding multilayers annealed at atmospheric pressure in a mixture of H2 and Ar. This vacuum-annealing process will offer potential advantages, enabling a continuous batch process from the deposition to the annealing. Their giant magnetoresistive behaviors were attributed to the magnetostatic coupling that are induced at the edges of the discontinuous magnetic grains. We also present our results about the multilayer patterned into a basic device for the magnetic field sensor.

• Journal of Magnetics
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• v.22 no.1
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• pp.7-13
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• 2017

The magnetoresistance (MR) properties of antiferromagnetic (AFM) IrMn based giant magnetoresistance-spin valve (GMR-SV) was investigated in view point of the artificial rotation effect of ferromagnetic (FM) layer in the plane induced by an applied field during the post annealing temperature. The MR curves measured with an azimuthal angle region of ${\phi}=0^{\circ}-360^{\circ}$ are depended on the annealing temperature and the magnetization easy axis of two free NiFe layers and two pinned NiFe layers in dual-type GMR-SV film. Especially, the annealing temperature and sample rotation angle(${\theta}$ ) maintained to the magnetic sensitivity (MS) of 1.4 %/Oe with an isotropic region angle of $110^{\circ}$ are $100^{\circ}C$ and $90^{\circ}$, respectively.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.6
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• pp.282-287
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• 2009

$Ni_xFe_{100-x}$ films with a thickness of about 100nm were deposited on Si(100) substrates at room temperature by a DC magnetron co-sputtering using Fe and Ni targets. Compositional, structural, electrical and magnetic properties of the films were investigated. $Ni_{67}Fe_{33}$, $Ni_{55}Fe_{45}$, $Ni_{50}Fe_{50}$, $Ni_{45}Fe_{55}$, $Ni_{40}Fe_{60}$ films are obtained by increasing the sputtering power of the Fe target. The films of x < 55 have BCC structure and show the phase transformation after annealing at the range of $300{\sim}450^{\circ}C$ for 2 h. On the other hand, the films of x < 50 have the mixed crystalline phases of BCC and FCC after the annealing treatment. The saturation magnetization was decreased initially by the phase transformation effect but then increased again after annealing at $450^{\circ}C$ due to the grain growth and crystallization of BCC phases.

• Journal of the Korean Magnetics Society
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• v.14 no.5
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• pp.163-168
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• 2004

We prepared ultra thin film structure of Si(100)/ $SiO_2$(200 nm)/Ta(5 nm)/Ni$_{80}$Fe$_{20/(l～15 nm)}$Ta(5 nm) using an inductively coupled plasma(ICP) helicon sputter. Magnetic properties and cross-sectional microstructures were investigated with a superconduction quantum interference device(SQUID) and a transmission electron microscope(TEM), respectively. We report that NiFe films of sub-3 nm thickness show the B$_{bulk}$ = 0 and B$_{surf}$=-3 ${\times}$ 10$^{-7}$(J/$m^2$). Moreover, Curie temperature may be lowered by decreasing thickness. Coercivity become larger as temperature decreased with 0.5 nm - thick Ta/NiFe interface intermixing. Our result implies that effective magnetic properties of magnetoelastic anisotropy, saturation magnetization, and coercivity may change abruptly in nano-thick films. Thus we should consider those abrupt changes in designing nano-devices such as MRAM applications.

• Journal of the Korean Magnetics Society
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• v.14 no.6
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• pp.224-227
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• 2004

We have studied local magnetization reversal by laser annealing in exchange biased NiFe/FeMn bilayer. Local magnetization reversal was performed by using the DPSS laser under external magnetic field of 600G. When the laser illuminated the patterned film with the power of above 300 mW during 15 min, a magnetoresistance (MR) curve with symmetric peaks at the opposite field was obtained due to the local reversal of exchange biasing. The direction of exchange anisotropy in the locally reversed region can be restored by local laser annealing under alternating magnetic field, even if its MR peak was reduced by the damage and interdiffusion. The magnetic domain structure of the locally reversed region was measured by MFM. The new domains were generated by laser annealing near the exposed area.