• Journal of the Korean Magnetics Society
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• v.11 no.4
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• pp.173-178
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• 2001

The effects of heat-treatment with magnetic or non-magnetic field on magnetic properties of gas-atomized MPP dust cores subjected to various cooling processes after annealing were investigated. Upon magnetic-field annealing, ac permeability and core loss decreased with the increase of cooling rate, which were attributed to the generation of inhomogeneous internal stress and anomalous eddy current loss, respectively. It was not observed the formation of ordered phase and the related change in magnetic properties at the cooling stage for MPP dust cores. In MPP alloys, magnetic anisotropy was easily induced through the directional order, and permeability and core loss were changed under the conditions of low cooling rate and magnetic annealing.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.59-72
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• 1999

In this thesis, we measured the Barkhausen effect of CoFeSiB amorphous ribbon and then investigated its possibility to be used as a sensor material. We used a sample of composition $($Fe_{0.06}$$Co_{0.94}$)_${0.79}$$Si_{2.1}$$B_{18.9}$ with a thickness 12[pm1, width 2.5[rnml and length 5[cm], which was fabricated by a single roll method. In order to improve magnetic characteristics of the sample, we had carried on annealing in the magnetic field and in none magnetic field. And, experimented results to the magnetic characteristics show that the ribbon has large Barkhausen jump even in weak magnetic field below 0.5[0el. From the results, we confirmed that the sample can be used as an magnetic sensor material.

• Journal of the Korean Magnetics Society
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• v.4 no.2
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• pp.150-153
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• 1994

Magnetic field annealing method has been used to obtain proper hysteresis loop shapes which are useful to a device using amorphous ribbon. In this study, two pairs of Helmhotz coils were used to apply longitudinal and transverse magnetic field during annealing. For the measurement of coercive field strength noise which depends on magnetic field annealing, Co-based amorphous alloy ribbon $VITROVAC^{\circledR}$ 6030 was used. For the sample which was annealed under dc transverse and dc longitudinal magnetic field, coercive field strength noise was nearly independent of magnetizing frequency ranging from 1 to 100 kHz, but dc transverse and ac longitudinal magnetic fields annealed samples show that the coercive field strength noise decreased in power of magnetizing frequency. When magnetic domain nucleation occurred, the coercive field strength noise increased remarkably and decreased in power of magnetizing frequency.

• Transactions on Electrical and Electronic Materials
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• v.8 no.1
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• pp.32-35
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• 2007

In this article, a novel annealing technique using alternating magnetic field (AMF) is adopted to improve the electrical characteristics of pentacene film, thereby enhancing the performance of pentacene-based organic thin film transistors (OTFTs). According to the investigation results, the electrical conductivity in the pentacene film could be increased from 0.32 to 1.18 S/cm by annealing the pentacene film using AMF. And also, OTFTs with the pentacene film annealed by AMF exhibited an improved performance compared to the device without annealing. These results suggest that an annealing using AMF can be an effective method to improve the performance of devices based on organic semiconductors.

• Proceedings of the Korean Magnestics Society Conference
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• 1997.05a
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• pp.70-71
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• 1997

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1989.06a
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• pp.49-51
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• 1989

The effect of Mo elenent and annealing condition on the magnetic properties were investigated in Fe$_{80}$B$_{12}$Si$_{8}$ amorphous alloy. With increasing Mo contents, soft magnetic properties were improved by decreasing coercive force and increasing maximum permeability. These improvements were attributed to the decreasing of magnetostriction by Mo addition. The annealing treatment also improved the soft magnetic properties of (Fe$_{1-x}$ Mo$_{x}$)$_{80}$ B$_{12}$ Si$_{8}$ amorphous alloys. It could be thought that these improvements were ascribed to the relaxation of internal stress.nal stress.ess.

• Journal of the Korean Magnetics Society
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• v.25 no.2
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• pp.47-51
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• 2015

To achieve a high tunneling magneto resistance (TMR) of sputtered magnetic tunnel junctions (MTJs) with an MgO barrier, the annealing process is indispensable. The structural and compositional changes as consequences of the annealing greatly affect the spin-dependent transport properties of MTJs. Higher TMR could be obtained for MTJs annealed at higher annealing temperature. The diffusion of Ru, Mn and/or Ta in the MTJs may occur during annealing process, which is known to be detrimental to spin-dependent tunneling effect. The rapid thermal annealing (RTA) process was used for annealing the MTJs with synthetic antiferromagnets. To suppress the diffusion of Mn, Ru and/or Ta in the MTJs, the process time and temperature of RTA were minutely controlled.

• Journal of Magnetics
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• v.11 no.2
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• pp.66-69
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• 2006

Local magnetization reversal in the exchange-biased NiFe/FeMn and $[Pd/Co]_5/FeMn$ multilayers with in-plane and out-of-plane magnetic anisotropy was achieved by using laser annealing. The local annealed NiFe/FeMn film under the opposite magnetic field shows a magnetoresistance (MR) curve having two symmetric peaks at the positive and negative exchange biasing field (${\pm}H_{ex}$). The intensity of the nucleated MR peak rises as the exposed area extends during the laser annealing process, and the peak disappears under the reverse magnetic field. In the case of [Pd/Co]/FeMn films, the local magnetization reversal increased gradually as the laser power increases. The locally reversed magnetization was restored under the opposite magnetic field.

• Korean Journal of Materials Research
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• v.14 no.2
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• pp.94-100
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• 2004

We have investigated the magnetic domain structure and the thermal stability of magnetotransport properties of IrMn biased spin-valves containing Co, CoFe and NiFe. The magnetic domain structures were imaged using a magneto-optical indicator film(MOIF) technique. To investigate the thermal stability, magnetoresistance(MR) was measured at annealing temperature(TANN) and room temperature($T_{RT}$) followed by the annealing. Domain imaging reveal that the increase of annealing temperature led to changes in the exchange coupling between the two ferromagnet(FM) layers through nonmagnetic layer rather than between FM and antiferromagnet. unlike the NiFe biased IrMn spin valve with large domains, MOIF pictures of Co and CoFe biased IrMn spin valve structures show the formation of many small microdomains. The magnetic structure, as revealed by the domain images, appeared unchanged while the MR dropped dramatically. From the combined giant magnetoresistance(GMR) and MOIF results, it was apparent that the decrease of MR ratio was not related to the spin valve magnetic structure up to about $350^{\circ}C$($T_{RT}$ ).

• Journal of the Korean Society for Heat Treatment
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• v.19 no.4
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• pp.208-218
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• 2006

The effects of the grain size on the magnetic properties in extra-low carbon steel after strain annealing were investigated. Two kinds of sample were prepared. One is the annealed sheet, which was annealed at $670^{\circ}C$ and $850^{\circ}C$ for various time periods after cold rolling. The other is the strain annealed sheet, which was temper rolled by 0.4% and subsequently strain annealed at the temperature ranging between $670^{\circ}C$ and $850^{\circ}C$ for various time periods. The grains after strain annealing became more coarse than those after primary annealing. The grains were coarsened due to the strain induced grain boundary migration (SIGM). It was found that the permeability tended to be increased and coercivity tended to be decreased with the increase of grain size. The optimum magnetic properties was achieved after strain annealing at $850^{\circ}C$ for 30 minites. Under this condition, the coercivity was measured to be 0.6 and the permeability was measured up to be 13000.