• Title, Summary, Keyword: anisotropy coupling

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Anisotropy Coupling in Patterned Thin Films with Mixed Uniaxial Anisotropies

  • Nam, Yoon Jae;Lee, Tae Young;Lim, Sang Ho
    • Journal of Magnetics
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    • v.19 no.3
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    • pp.232-236
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    • 2014
  • Anisotropy coupling in thin films with mixed induced and shape anisotropies is investigated. A 200-nm-thick Co-Fe-Pd-B thin film with a large induced anisotropy of 57 Oe is fabricated and then patterned into micron-sized cells to provide shape anisotropy, whose strength has a similar magnitude to that of the induced anisotropy for enhancing the anisotropy coupling. The angles between the two mixed anisotropies considered are $0^{\circ}$, $90^{\circ}$, and $110^{\circ}$. Hysteresis loops measured under in-plane magnetic fields along various directions indicate no anisotropy coupling behaviour for all the three angles examined in this study.

Polarization Mode Coupling Constants in Solid-State Lasers

  • Park, Jong-Dae;Cho, Chang-Ho
    • The Journal of Natural Sciences
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    • v.17 no.1
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    • pp.31-37
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    • 2006
  • We have found that the polarization mode coupling between the orthogonally linearly polarized dual mode laser results from the anisotropy of dipole moments. Rate equation analysis demonstrated that high anisotropy in dipole moment components can give rise to law intrinsic mode coupling constants while isotropic dipole moment components give high intrinsic mode coupling constant. The populations at active ion sites are shown to self-organize the populations such that laser mode gain is constant adove threshold while the gain contributions from the each site adjust themselves with pump power.

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Anisotropy Angle Dependence of Interlayer Exchange Coupling of Perpendicular Magnetic [CoFe/Pt/CoFe]/IrMn Multilayers ([CoFe/Pt/CoFe]/IrMn 다층박막의 수직자기 이방성 각도에 따른 상호교환결합력 특성)

  • Lee, Sang-Suk;Choi, Jong-Gu;Hwang, Do-Guwn;Rhee, Jang-Roh
    • Journal of the Korean Magnetics Society
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    • v.18 no.6
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    • pp.232-236
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    • 2008
  • Dependence of interlayer exchange coupling on antiferromagnetic IrMn thickness, thermal stability, and parallel anisotropy angle in perpendicular anisotropy [CoFe/Pt/CoFe]/IrMn multilayers was investigated. The magnetic property of [CoFe($10{\AA}$)/Pt($8{\AA}$)/CoFe($10{\AA}$)] induced by antiferromagnetic ordering of IrMn layer was maintained a stable perpendicular anisotropy up to $250^{\circ}C$ and from $7{\AA}$ to $160{\AA}$ of IrMn thickness. The value of interlayer exchange coupling of [CoFe/Pt/CoFe]/IrMn multilayers with perpendicular anisotropy increased to 1.5 times at anisotropy angle of $60^{\circ}$ more than of $0^{\circ}$. On the other side, the interlayer exchange coupling at anisotropy angle of $90^{\circ}$ was $\infty$ Oe, it was likely diverted to a parallel shape magnetization.

NiO Thickness Dependences of Perpendicular Magnetic Anisotropy in the [CoFe/Pt] Multilayers

  • Kim, S.W;Lee, J.Y;Lee, S.S;Hahn, E.J;Hwang, D.G
    • Journal of Magnetics
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    • v.9 no.4
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    • pp.121-124
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    • 2004
  • NiO thickness dependences of perpendicular magnetic anisotropy (PMA) in the $NiO/[CoFe/Pt]_5$ multilayers for exchange biasing and $[CoFe/Pt]_4/Pt/[CoFe/Pt]_4$ for interlayer exchange coupling were investigated. Perpendicular magnetization curve was obtained by out-of-plane extraordinary Hall measurement. Magnetic force microscopy (MFM) has been used for the investigation of magnetic domains on thin films. We confirmed that the interlayer exchange coupling (IEC) as a function of NiO thickness at room temperature existed with a period of two monolayers.

Pt Thickness Dependence of Oscillatory Interlayer Exchange Coupling in [CoFe/Pt/CoFe]/IrMn Multilayers with Perpendicular Anisotropy

  • Lee, Sang-Suk;Choi, Jong-Gu;Kim, Sun-Wook;Hwang, Do-Guwn;Rhee, Jang-Roh
    • Journal of Magnetics
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    • v.10 no.2
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    • pp.44-47
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    • 2005
  • The oscillatory interlayer exchange coupling (IEC) has been shown in pinned $[CoFe/Pt(t_{pt})/CoFe]/IrMn$ multi-layers with perpendicular anisotropy. The period of oscillation corresponds to about 2 monolayers of Pt. The oscillatory behavior of IEC depending on the nonmagnetic metallic Pt thickness is thought to be related the antiferromagnetic ordering induced by IrMn layer. Oscillatory IEC as function of insulating NiO thickness has been observed in $[Pt/CoFe]_4/NiO(t_{NiO})/[CoFe/Pt]_4$ multilayers. The effect of N (number of bilayer repeats) upon the magnetic property of [Pt/CoFe]N/IrMn is also studied.

Hysteresis Loops of Magnetically Coupled Multilayers - Experiment and Calculations

  • Czapkiewicz, M.;Stobiecki, T.;Rak, R.;Wrona, J.;Kim, C.G.
    • Journal of Magnetics
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    • v.9 no.2
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    • pp.60-64
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    • 2004
  • In this paper calculations of magnetisation and magnetoresistance characteristics of the Spin Valve (SV) and Pseudo Spin Valve (PSV) spintronics structures are reported and compared with the experimental data. The magnetisation reversal process was analysed with respect to the Stoner- Wohlfahrt model of total surface energy in terms of uniaxial anisotropy, exchange coupling between ferromagnetic layers, unidirectional exchange anisotropy of pinned layer (modelled by exchange coupling between magnetisation of pinned layer and net magnetisation of antiferromagnetic layer with high anisotropy). The numerical simulation of the model to the experimental magnetisation data yielded the above parameters for SV and PSV structures. These parameters were used to more sophistically micromagnetic modelling tool originating from the project called Object Oriented Micromagnetic Framework. Influence of the shape anisotropy of the Magnetic Tunnelling Junction cell used in MRAM was simulated by means of micromagnetic simulations. Results were compared to those obtained from the spot Kerr measurements.

OSCILLATORY MAGNETIC ANISOTROPY IN Fe/Cr/Fe TRILAYERS (Fe/Cr/Fe 삼층구조에서의 진동하는 자기이방성)

  • Kim, Ki-Yeon;Kim, Dong-Hyun;Shin, Sung-Chul;You, Chun-Yeol
    • Proceedings of the Korean Magnestics Society Conference
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    • pp.194-195
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    • 2002
  • Fe/Cr/Fe trilayers have attracted much interest from both theoretical and experimental aspects due to many novel magnetic properties such as antiferromagnetic coupling, giant magnetoresistance, oscillatory bilinear and biquadratic coupling [1]. In this work, we report that there is an oscillation of magnetic anisotropy with increasing intervening Cr layer thickness in Fe/Cr/Fe trilayers. (omitted)

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Rotatable Anisotropy Field in Exchange Coupled CoFe/MnIr(2.5 nm) Thin Films (교환 결합력을 갖는 CoFe/MnIr(2.5 nm) 박막의 회전 이방성 자기장 특성)

  • Yoon, Seok Soo;Kim, Dong Young
    • Journal of the Korean Magnetics Society
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    • v.27 no.3
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    • pp.77-81
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    • 2017
  • The rotatable anisotropy effect was observed in the ferromagnetic resonance measurement in exchange coupled ferromagnetic/antiferromagnetic thin films and it was due to rotation of antiferromagnetic layer by the exchange coupling energy. We analyzed the CoFe thickness dependence of rotatable anisotropy field and ferromagnetic resonance linewidth in exchange coupled $CoFe(t_F)/MnIr(2.5nm)$ thin films. The rotatable anisotropy field was inversely propositional to the CoFe thickness and it was well fitted by the rotatable anisotropy energy of $0.96erg/cm^2$. The ferromagnetic resonance linewidth were linearly propositional to the rotatable anisotropy field in $t_F$ < 50 nm, while it was more dominated by the eddy current effect in $t_F$ > 50 nm.

Interfacial Charge Transport Anisotropy of Organic Field-Effect Transistors Based on Pentacene Derivative Single Crystals with Cofacial Molecular Stack (코페이셜 적층 구조를 가진 펜타센 유도체 단결정기반 유기트랜지스터의 계면 전하이동 이방성에 관한 연구)

  • Choi, Hyun Ho
    • Journal of Adhesion and Interface
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    • v.20 no.4
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    • pp.155-161
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    • 2019
  • Understanding charge transport anisotropy at the interface of conjugated nanostructures basically gives insight into structure-property relationship in organic field-effect transistors (OFET). Here, the anisotropy of the field-effect mobility at the interface between 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-pentacene) single crystal with cofacial molecular stacks in a-b basal plane and SiO gate dielectric was investigated. A solvent exchange method has been used in order for TIPS-pentacene single crystals to be grown on the surface of SiO2 thin film, corresponding to the charge accumulation at the interface in OFET structure. In TIPS-pentacene OFET, the anisotropy ratio between the highest and lowest measured mobility is revealed to be 5.2. By analyzing the interaction of a conjugated unit in TIPS-pentacene with the nearest neighbor units, the mobility anisotropy can be rationalized by differences in HOMO-level coupling and hopping routes of charge carriers. The theoretical estimation of anisotropy based on HOMO-level coupling is also consistent with the experimental result.