• Proceedings of the Korean Magnestics Society Conference
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• 2004.06a
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• pp.66-67
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• 2004

• Journal of Magnetics
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• v.14 no.1
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• pp.36-41
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• 2009

Magneto-optical Kerr effect (MOKE) magnetometry was used to investigate magnetization reversal dynamics in 30-nm NiFe/15-nm FeMn, 15-nm FeMn/30-nm CoFe bilayers, and 30-nm NiFe/(2,10)-nm FeMn/30-nm CoFe trilayers. The in-plane magnetization components of each ferromagnetic layer, both parallel and perpendicular to the applied field, were separately determined by measuring the longitudinal and transverse MOKE hysteresis loops from both the front and back sides of the film for an oblique incident s-polarized beam. The magnetization of the FeMn/CoFe bilayer was reversed abruptly and symmetrically through nucleation and domain wall propagation, while that of the NiFe/FeMn bilayer was reversed asymmetrically with a dominant rotation. In the NiFe/FeMn/CoFe trilayers, the magnetic reversal of the two ferromagnetic layers proceeded via nucleation and domain wall propagation for 2-nm FeMn, but via asymmetric rotation for 10-nm FeMn. The exchange-biased ferromagnetic layers showed the magnetization reversal along the same path in the film plane for the decreasing and increasing field branches from transverse MOKE hysteresis loops, which can be qualitatively explained by the theoretical model of the exchange-biased ferromagnetic/antiferromagnetic systems.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.1050-1053
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• 2001

There is great interest in developing magnetoresistance(MR) sensor, using ferromagnetic, electrically non-magnetic conducting and antiferromagnetic films, especially for the use in weak magnetic fields. Here, we report single and Wheatstone-bridge type of MR sensors made in Si(001)/HiO(300$\AA$)/NiFe bilayers. Angular dependence of MR profiles was measured in Si(001)/NiO(300$\AA$)/NiFe(450$\AA$) films as a function of an angle between current and applied field direction, also, linearity was determined. AMR characteristics of single MR sensors was well explained with single domain model. Good linearity in 45$^{\circ}$Wheatstone-bridge type of MR sensors consisting of 4 single MR sensors made in Si(001)/NiO(300$\AA$)/NiFe(450$\AA$) was shown in the range of about $\pm$50 Oe.

• Proceedings of the Korean Magnestics Society Conference
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• 2016.11a
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• pp.56-57
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• 2016

• Journal of the Korean Magnetics Society
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• v.1 no.2
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• pp.31-36
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• 1991

Structural and compositional heterogeneities of sputter deposited, amorphous $Co_{87}Zr_{4}NB_{9}$ thin films were investigated using TEM and EDS with windowless detector. The films deposited with substrate bias and annealed in rotating magnetc field showed two amorphous phases of Co-rich region and (ZrNb)oxide-rich region, and revealed 'ultra-soft' magnetic properties. Revesible bias-responses and overdamped frequency responses, along with small Hc, Hk and Mr/Ms ratio, give the possibility of ultra-soft magnetic behavior fo CoZrNb thin films. We proposed the vortex type magnetization distribution in remanent state which was correlated with the thin film heterogeneity. Then, the ultra-soft characteristics of the compositionally heterogeneous films were explained by the spin vortices that minimized the total magnetostatic and exchange coupling energies.

• Journal of the Korean Magnetics Society
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• v.11 no.4
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• pp.141-145
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• 2001

The Mn$\_$80/Ir$\_$18.1/Pt$\_$1.9/ exchange bias layers (EBLs), which have a small amounts of Pt, exhibit a high value of H$\_$ex/. The Si/Ni-Fe/Mn$\_$80/Ir$\_$18.1/Pt$\_$1.9/ EBL shows the largest H$\_$ex/ of 187 Oe, which is equivalent to a exchange energy (J$\_$ex/) of 0.146 erg/cm$^2$. Mn$\_$80/Ir$\_$18.1/Pt$\_$1.9/ EBLS are estimated to have blocking temperature of about 250 $\^{C}$, which is higher than those of Mn-Ir EBLs and Mn-Ir-Pt EBLs with higher Pt contents. This result implies that a little addition of Pt element promotes thermal stability in the Mn-Ir-Pt EBLs. The chemical stability of Mn-Ir-Pt EBLs was characterized by potentiodynamic test, which was performed in 0.001 M NaCl solution. The current density of Mn-Ir-Pt films was gradually reduced with increasing Pt content. The present results indicate that the Mn-Ir-Pt with a small amount of Pt is suitable for an antiferromagnetic material for a reliable spin valve giant magnetoresistance device.

• Journal of the Korean Magnetics Society
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• v.14 no.5
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• pp.192-195
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• 2004

Magnetic properties by exchange biased perpendicular magnetic anisotropy in [Pd(0.8 nm)/Co(0.8 nm)]$_{5}$/FeMn(15 nm) multilayers deposited by dc magnetron sputtering system are investigated. As inserted Pd layer of interface between [Pd/Co] multilayer and FeMn film, the Hex of perpendicular anisotropy was improved from 127 Oe to 145 Oe. But result of an experiment by thermal stability, the Hex of the case that an inserted layer was inserted in decreased from low 20$0^{\circ}C$ in about 5$0^{\circ}C$ more if not inserted. If Ta was a buffer layer, the experiment results along material of buffer layer, the H$_{ex}$ obtained the largest 127 Oe. And if Pd was a buffer layer, H$_{ex}$ obtained the largest 169 Oe. Also, the Hc in buffer layer of Ta and Pd obtained the largest 203 Oe and 453 Oe, respectively.

• Progress in Superconductivity and Cryogenics
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• v.19 no.3
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• pp.23-26
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• 2017

We have studied magnetic and transport properties of NbN/FeN/Cu/FeN/FeMn spin-valve structure. In-plane magnetic moment exhibited typical hysteresis loops of spin valves in the normal state of NbN film at 20 K. On the other hand, the magnetic hysteresis loop in the superconducting state exhibited more complex behavior in which exchange bias provided by antiferrmagnetic FeMn layer to adjacent FeN layer was disturbed by superconductivity. Because of this, the ideal superconducting spin-valve effect was not detected. Instead the stray field originated from unsaturated magnetic states dominated the transport properties of NbN/FeN/Cu/FeN/FeMn multilayer.

• Proceedings of the Korean Magnestics Society Conference
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• 2000.09a
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• pp.329-330
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• 2000

• Journal of the Korean Magnetics Society
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• v.27 no.3
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• pp.82-86
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• 2017

The IrMn based GMR-SV films with three different buffer layers were prepared on Corning glass by using ion beam deposition and DC magnetron sputtering method. The major and minor magnetoresistance curves for three different buffer layers beneath the structure of NiFe(15 nm)/CoFe(5 nm)/Cu(2.5 nm)/CoFe(5 nm)/NiFe(7 nm)/IrMn(10 nm)/Ta(5 nm) at room temperature have shown different magnetoresistance properties. When the samples were annealed at $250^{\circ}C$ in vacuum, the magnetoresistance ratio, the coercivity of pinned ferromagnetic layer, and the interlayer coupling field of free ferromagnetic layer were enhanced while the exchange bias coupling field did not show noticeable changes.