• Title/Summary/Keyword: 자성층 용이축

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Comparison of Soft Magnetic Properties of Permalloy and Conetic Thin Films (퍼멀로이와 코네틱 박막의 연자성 특성 비교)

  • Choi, Jong-Gu;Hwang, Do-Guwn;Lee, Sang-Suk;Rhee, Jang-Roh
    • Journal of the Korean Magnetics Society
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    • v.19 no.4
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    • pp.142-146
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    • 2009
  • The soft magnetic property for the Corning glass/Ta(5 nm)/[Conetic, Permalloy)/Ta(3 nm) prepared by the ion beam deposition sputtering was investigated. The coercivity and saturation magnetic field of conetic (NiFeCuMo) and permalloy (NiFe) layer with easy and hard direction along to the applying magnetic field during deposition was compared with each other. The surface resistance of conetic film with a thickness of 10 nm was 2 times lower than one of permalloy film. The coercivity and the magnetic susceptibility of conetic film decreased and increased 3 times to one of permalloy film, respectively. These results suggest that a highly sensitive GMR-SV or MTJ using conetic film can be possible to develop the bio-device.

Post-annealing Effect of Giant Magnetoresistance-Spin Valve Device for Sensor (센서용 거대자기저항 스핀밸브소자의 열처리 효과)

  • Lee, Sang-Suk;Park, Sang-Hyun;Soh, Kwang-Sup;Joo, Ho-Wan;Kim, Gi-Wang;Hwang, D.G.
    • Journal of the Korean Magnetics Society
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    • v.17 no.4
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    • pp.172-177
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    • 2007
  • In order to detect of the magnetic property in the cell unit, we studied the GMR-SV (giant magnetoresistance-spin valves) biosensor, which was depended on the micro patterned features according to two easy directions of longitudinal and transversal axes. Here, the multi layer structure was glass/NiO/NiFe/CoFe/Cu/CoFe/NiFe. The uniaxial anisotropy direction was applied to the patterned biosensor during the deposition and vacuum post-annealing at $200^{\circ}C$ under the magnitude of 300 Oe, respectively. Considering the magnetic shape anisotropy effect, the size of micro patterned biosensor was a $2{\times}5{\mu}m^2$ after the photo lithography process. By our experimental results, we confirmed that the best condition of GMR-SV biosensor should be the same direction of the axis sensing current and the easy axis of pinned NiO/NiFe/CoFe triple layer oriented to the width direction of device, and the direction of the easy axis of free CoFe/NiFe bilayer was according to the longitudinal direction of device.

Soft Magnetoresistive Properties of Conetic Thin Film Depending on Ta Buffer Layer (버퍼층 Ta에 의존하는 코네틱 박막의 연자성 자기저항 특성)

  • Choi, Jong-Gu;Hwang, Do-Guwn;Lee, Sang-Suk;Choi, Jin-Hyub;Lee, Ky-Am;Rhee, Jang-Rho
    • Journal of the Korean Magnetics Society
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    • v.19 no.6
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    • pp.197-202
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    • 2009
  • The property of soft magnetism for the Corning glass/non-buffer or buffer Ta/Conetic(NiFeCuMo)/Ta prepared by the ion beam deposition sputtering was studied. The effect of crystal property and post annealing treatment depending on the thickness of Conetic thin films was investigated. The coercivities of Conetic thin films with easy and hard direction along to the applying magnetic field during deposition were compared with each other. The coercivity and magnetic susceptibility of Ta(5 nm)/Conetic(50 nm) thin film were 0.12 Oe and 1.2 ${\times}\;10^4$, respectively. From these results, firstly, the Conetic thin film was more soft magnetism thin film than other one such as permalloy NiFe. Secondly, the usage of soft magnetism Conetic thin film for GMR-SV (giant magneoresistance-spin valve) or MTJ (Megnetic Tunnel Junction) structure in a low magnetic field can be possible.

Soft Magnetic Property Depending on thickness of Free Layer in CoFe/Cu/CoFe/IrMn Spin Valve Film (CoFe/Cu/CoFe/IrMn 스핀밸브 박막의 자유층 두께 감소에 따른 연자성 자기저항 특성 연구)

  • Choi, Jong-Gu;Go, In-Suk;Gong, Yu-Mi;Kim, Min-Ho;Park, Young-Suk;Hwang, Do-Guwn;Lee, Sang-Suk
    • Journal of the Korean Magnetics Society
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    • v.19 no.2
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    • pp.52-56
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    • 2009
  • Interlayer coupling field, coercivity, magnetoresitance ratio, and magnetic sensitivity depending on the thickness of free CoFe layer for the CoFe/Cu/CoFe/IrMn multilayer are investigated. In case of CoFe layer of $30\;{\AA}$ thickness for the CoFe(t)/Cu($25\;{\AA}$)/CoFe($60\;{\AA}$)/IrMn($80\;{\AA}$) multilayer with ferromagnet/non-magnet/ferromagnet structure induced by IrMn layer, the lowest coercivity and the highest magnetic sensitivity, which is contained soft magnetic property, are observed. On the other side, in case of CoFe layer of $90\;{\AA}$ thickness, there are the highest coercivity and the lowest magnetic sensitivity. The fabricated CoFe($30\;{\AA}$)/Cu($25\;{\AA}$)/CoFe($60\;{\AA}$)]/IrMn($80\;{\AA}$) spin valve device with $2{\times}8{\mu}m^2$ patterning size are measured by two probe method, which is selected the sensing current as the longitudinal direction and the easy axis as the transversal direction. The measuring magntoresistance ratio and magnetic sensitivity of GMR-SV device having the soft magnetic property are 3.0% and 0.3%/Oe, respectively.

Understanding the Surface Magneto-optic Kerr Effect (표면 자기광 커 효과의 이해)

  • Hwang, Chan-Yong
    • Journal of the Korean Magnetics Society
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    • v.21 no.4
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    • pp.141-146
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    • 2011
  • We will introduce the surface magneto-optic Kerr effect (SMOKE), which is one of the most helpful experimental methods in the area of surface magnetism for the last two decades. The basic magnetic characteristics of magnetic thin film is the most essential part for the further understanding and application. For example, the possibility of the realization of ferromagnetism for a single layer of iron, its Curie temperature far below that of bulk iron, and the direction of easy axis are the fundamental questions for the spintronic application. SMOKE is an efficient method to answer for the questions above.

Magnetic Properties of Three-layered Ferromagnetic Films with a NiFeCuMo Intermediately Super-soft Magnetic Layer (강자성층 사이에 초연자성 NiFeCuMo 중간층을 삽입한 3층 박막구조의 자기적 특성)

  • Choi, Jong-Gu;Lee, Sang-Suk
    • Journal of the Korean Magnetics Society
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    • v.20 no.4
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    • pp.129-133
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    • 2010
  • Two-layered ferromagnetic alloy films (NiFe, CoFe) with a Conetic (NiFeCuMo) intermediately soft magnetic layer of different thickness were investigated to correlate the coercivity values and magnetization process with the strength of saturation field of hard axis. Thickness dependence of the $H_{EC}$ (coercivity of easy axis), $H_{HS}$ (saturation field of hard axis.), and X (susceptibility) of NiFe and NiFeCuMo thin films for the glass/Ta(5 nm)/[CoFe or NiFe(5 nm-t/2)]/NiFeCuMo(t = 0, 4, 6, 8, 10 nm)/[CoFe or NiFe(5 nm-t/2)]/Ta(5 nm) films prepared by the ion beam deposition method was measured. The magnetic properties $H_{EC}$, $H_{HS}$, and X of two-layered ferromagnetic CoFe, NiFe films with a NiFeCuMo intermediately super-soft magnetic layer were strongly depended on the thickness of NiFeCuMo layer. The value of the coercivity and magnetic susceptibility of the NiFeCuMo film decreased by 25% and doubled relative to that of the NiFe film.

Magnetoresistive Properties of Array IrMn Spin Valves Devices (어레이 IrMn 스핀밸브 소자의 자기저항특성 연구)

  • Ahn, M.C.;Choi, S.D.;Joo, H.W.;Kim, G.W.;Hwang, D.G.;Rhee, J.R.;Lee, S.S.
    • 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.

MnIr Thickness Dependence of Torque Signals in CoFe/MnIr Thin Films (CoFe/MnIr 박막 재료에서 MnIr의 두께에 따른 토오크 신호 분석)

  • Kim, Dong Young;Yoon, Seok Soo
    • Journal of the Korean Magnetics Society
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    • v.24 no.5
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    • pp.140-145
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    • 2014
  • We analyzed the MnIr thickness dependence of torque signals measured in exchange coupled CoFe/MnIr ($t_{AF}$) bilayers. The measured torque signals were compared with calculated ones by Stoner-Wohlfarth model. The exchange coupling anisotropy $J_c$ was considered for the model calculation between ferromagnetic (F) and antiferromagnetic (AF) layers with uniaxial anisotropy constant of $K_F$ and $K_{AF}$, respectively. The rotational losses were appeared in the range of $0.5t_c$ < $t_{AF}$ < $t_c$ ($=J_c/K_{AF}$) by the unpinned AF layer. While, the unidirectional anisotropy ($J_k$) was caused by the pinned AF layer at $t_{AF}$ > $t_c$. The critical thickness of MnIr layer was $t_c$ = 3.4 nm in CoFe/MnIr bilayers. The rotational losses behavior as shown in $t_{AF}$ = 3 nm sample were explained by the random orientation of the easy axis of AF grains. The unidirectional anisotropy obtained from torque signal of $t_{AF}$ = 10 nm sample was $J_k=0.63J_c$. Thus, the unidirectional anisotropy can be enhanced up to $J_k=J_c$ by aligning the AF easy axis.