• Proceedings of the Korean Magnestics Society Conference
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• 2009.12a
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• pp.172-173
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• 2009

• Proceedings of the Korean Magnestics Society Conference
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• 2003.06a
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• pp.118-119
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• 2003

• Proceedings of the Korean Magnestics Society Conference
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• 2012.11a
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• pp.28-28
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• 2012

• Proceedings of the Korean Magnestics Society Conference
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• 2012.11a
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• pp.55-56
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• 2012

• Proceedings of the Korean Magnestics Society Conference
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• 2011.12a
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• pp.85-86
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• 2011

• Journal of the Korean Magnetics Society
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• v.22 no.6
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• pp.204-209
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• 2012

We measure the ferromagnetic resonance signals in order to analyze the exchange coupling energy due to the uncompensated antiferromagnetic spins in exchange coupled CoFe/MnIr bilayers. The exchange bias fields ($H_{ex}$) and rotatable anisotropy fields ($H_{ra}$) are obtained from the ferromagnetic resonance fields measured with in-plane angle in thermal annealed samples with $t_{AF}$= 0, 3, and 10 nm. The sum of the $H_{ex}$ and $H_{ra}$ do not depend on the MnIr thickness, which means that all the uncompensated AF spins are aligned to one direction in $300^{\circ}C$ annealed samples. Therefore, the uncompensated AF spins are divided into two different parts. One parts are fixed at the interface between CoFe/MnIr bilayers and induces the $H_{ex}$, other parts are rotatable with magnetic field and induces the $H_{ra}$. Finally, the exchange coupling energy can be expressed by the sum of the exchange bias energy and rotatable anisotropy energy.

• Journal of the Korean Magnetics Society
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• v.12 no.3
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• pp.103-108
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• 2002

We investigated magnetoresistance(MR) and exchange bias properties by annealing in top and bosom type spin valves (SV) with nano-oxide layers (NOL). In top SVs with NOL, MR ratio of 9.2% is obtained after postdeposition annealing at 250$\^{C}$. In bottom SVs with NOL, MR ratio of 10.1 % is obtained after postdeposition annealing at 250$\^{C}$. Therefore, specular reflection of the NOL in bottom SVs is higher than that of the NOL in top SVs. Exchange biasing of bottom SVs with NOL is 28% higher than that of bottom SVs without NOL after annealing. This enhancement of exchange biasing is thought to be due to the reduced magnetic moment of the pinned layer with NOL and enhanced (111) FeMn texture.

• 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.

• Journal of the Korean Magnetics Society
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• v.25 no.3
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• pp.74-78
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• 2015

We measured the low field microwave absorption (LFMA) and ferromagnetic resonance (FMR) signals at various magnetic field angle in exchange biased CoFe/MnIr thin film. The LFMA signals were dominantly related to the magnetization rotation process. In order to analyze the LFMA signal, we calculated transverse magnetization ($M_{\tau}$) and permeability (${\mu}_{\tau}$) for CoFe/MnIr thin film by using S-W model, which magnetic parameters of exchange bias ($H_{ex}$ = 58.5 Oe) and uniaxial anisotropy field ($H_k$ = 30Oe) was obtained from FMR signals. The LFMA signal at hard axis showed similar behavior compared with that of $M_{\tau}$. As the magnetic field angle approach to the perpendicular to hard axis, the LFMA signals were depending on both of $M_{\tau}$ and ${\mu}_{\tau}$.

• Journal of the Korean Magnetics Society
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• v.18 no.4
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• pp.142-146
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• 2008

The angular dependence of the exchange bias($H_{ex}$) and coercivity($H_c$) in multilayer $[Pt/Co]_N-IrMn$ with applied measuring field rotated toward in-plane at angle $\theta$ from perpendicular-to-plane, has been measured. Multilayer films consisting of $Si/SiO_2/Ta(50)/Pt(4)/[Pt(15)/Co(t_{Co})]_N/IrMn(50)/Ta(50)(in\;{\AA})$ were prepared by magnetron sputtering under typical base pressure below $2{\times}10^{-8}$ Torr at room temperature. Magnetization measurements were performed on a vibrating sample magnetometer and extraordinary Hall voltage measurement systems after cooling from 550 K under a field of 2 kOe applied along the perpendicular to film direction. The hysteresis loop shifts from the origin not only along the field axis but also along the magnetization axis. $H_{ex}$ and $H_c$ show a $1/cos{\theta}$ and $1/|cos{\theta}|$ dependence on the angle($\theta$) between the applied measuring field and the perpendicular-film direction, respectively. This $1/cos{\theta}$ dependence can be accounted for by considering the angular dependence of strong out-of-plane magnetic anisotropy introduced during the field cooling.