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Hwang, T.J.;Kim, D.H.
- Progress in Superconductivity and Cryogenics
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- v.18 no.1
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- pp.33-36
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- 2016
Suppression of the superconducting transition temperature ($T_c$) of NbN thin films in superconductor/ferromagnet multilayers has been investigated. Both superconducting NbN and ferromagnetic FeN layers were deposited on thermally oxidized Si substrate at room temperature by using reactive magnetron sputtering in an $Ar-N_2$ gas mixture. The thickness of FeN films was fixed at 20 nm, while the thickness of NbN films was varied from 3 nm to 90 nm. $T_c$ suppression was clearly observed in NbN layers up to 70 nm thickness when NbN layer was in proximity with FeN layer. For a given thickness of NbN layer, the magnitude of $T_c$ suppression was increased in the order of Si/FeN/NbN, Si/NbN/FeN, and Si/FeN/NbN/FeN structure. This result can be used to design a spin switch whose operation is based on the proximity effect between superconducting and ferromagnetic layers.
https://doi.org/10.9714/psac.2016.18.1.033 인용 PDF KSCI

Lee, Sang-Suk;Hwang, Do-Guwn
- Journal of Magnetics
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- v.15 no.1
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- pp.17-20
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- 2010
The relationship between ferromagnet anisotropic magnetization and the antiferromagnet atomic spin configuration was investigated for various angles of the uniaxial deposition magnetic field of the FeMn layer in the Corning glass/Ta(5nm)/NiFe(7nm)/FeMn(25nm)/Ta(5nm) multilayer that was prepared by the ion beam sputter deposition. The exchange bias field ($H_{ex}$) obtained from the measurement of the easy-axis MR loop decreased to 40 Oe at the deposition field angle of $45^{\circ}$, and to 0 Oe at the angle of $90^{\circ}$. When the difference between the uniaxial axis between the ferromagnet NiFe and the antiferromagnet FeMn was $90^{\circ}$, the strong antiferromagnetic dipole moment of FeMn caused the weak ferromagnetic dipole moment of NiFe to rotate in the interface.
https://doi.org/10.4283/JMAG.2010.15.1.017 인용 PDF KSCI

Lee, W.Y;Bland, J.A.C
- Journal of Magnetics
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- v.7 no.1
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- pp.4-8
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- 2002
The magnetoresistance (MR) and the magnetization reversal of a lateral spin-injection device based on a spin-polarized field effect transistor (spin FET) have been investigated. The device consists of a two-dimensional electron gas (2DEG) system in an InAs single quantum well (SQW) and two ferromagnetic $(Ni_{80}Fe_{20})$ contacts: all injector (source) and a detector (drain). Spin-polarized electrons are injected from the first contact and, after propagating through the InAs SQW are collected by the second contact. By engineering the shape of the permalloy contacts, we were able to observe distinct switching fields $(H_c)$ from the injector and the collector by using scanning Kerr microscopy and MR measurements. Magneto-optic Kerr effect (MOKE) hysteresis loops demonstrate that there is a range of magnetic field (20~60 Oe), at room temperature, over which the magnetization in one contact is aligned antiparallel to that in the other. The MOKE results are consistent with the variation of the magnetoresistance in the spin-injection device.
https://doi.org/10.4283/JMAG.2002.7.1.004 인용 PDF KSCI

Dho Joonghoe
- Proceedings of the Korean Magnestics Society Conference
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- 2005.12a
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- pp.80-81
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- 2005
The resilience of the exchange bias ($H_{EX}$) in ferromagnet / antiferromagnet bilayers is generally studied in terms of repeated hysteresis loop cycling or by protracted annealing under reversed field (training and long-term relaxation respectively). The stability of $H_{EX}$ is fundamental for practical application of exchange bias systems. In this paper we report measurements of training and relaxation in FeNi films coupled with the antiferromagnet FeMn. We show that $H_{EX}$ suppressed both by training and relaxation was partially recovered as soon as a field cycling for consecutive hysteresis loop measurement was stopped or the magnetization of the ferromagnet was switched back to the biased direction.
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Lee, B.C.
- Journal of the Korean Magnetics Society
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- v.16 no.2
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- pp.121-129
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- 2006
The diffusion theory for spin injection from magnetic layer into nonmagnetic layer was reviewed. Basic equations were derived and applied to a ferromagnet/semiconductor/ferromagnet system. The spin polarization and magnetoresistance were calculated. The reason for difficulty in detecting spin injection with magnetoresistance was explained, and a possible solution was discussed.
https://doi.org/10.4283/JKMS.2006.16.2.121 인용 PDF KSCI