マグネティック・ナノイメージングと次世代磁気応用に関する研究会 ...
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マグネティック・ナノイメージングと次世代磁気応用に関する研究会 2003.10.29. 「シリコン埋め込みパーマロイ微細 十字パターン配列の磁気構造」 Magnetic structures in cross-shaped nano permalloy pattern-arrays embedded in silicon substrates. 佐藤勝昭、手塚智之、山本尚弘、町田賢司、石橋隆幸、森下義隆、纐纈明伯 K.Sato, T.Tezuka, T. Yamamoto, K.Machida, T. Ishibashi, Y. Morishita and A. Koukitu. - PowerPoint PPT PresentationTRANSCRIPT
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Magnetic structures in cross-shaped nano permalloy pattern-arrays embedded in silicon substratesK.Sato, T.Tezuka, T. Yamamoto, K.Machida, T. Ishibashi, Y. Morishita and A. Koukitu2003.10.29
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IntroductionVSM, MFM150nm100nm300nm100nm1000nmMFM
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Clean Room LaboratoryElectron beam lithography
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EB-patterning processDot sizesquare(1m 1m)rectangular(300nm100nm)circular(100 nm)cross(200nm3m, 100nm 1.5m) Patterned area: 3mm3mm4mm4mmEB-resist thickness: 300 nmby spin-coating with 5000 rpm rotationBaking16020minSpin coating of resistEB exposureSi substrateDevelopment
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Dry-etching
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Etching gas:CF4Vacuum3.010-3PaGas pressure 9.2PaRF power:400WEtching rate: 0.1m/minSilicon surface after etchingDry etching process
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LaboratoryEB depositionRF magnetron sputtering
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Embedding of permalloyEmbedding of permalloy film by electron beam depositionmaterial:permalloyNi80Fe20Vacuum3.010-6TorrAccelerating voltage 4kV Deposition rate 1.0/secPolishing chemicals: Polished by Kent3(Nanofactor)SlurryGRANZOX sp-15(Al2O3 powder)grain-size20nmpH11polishing rate:60nm/minflatteningChemical mechanical polishing (CMP)
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Observation/MFMFE-SEM
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SEM observation 300nm100nmsquare dot, 300 nm space
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Cross sectional SEM observation
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1m square dot arrayAFMMFM
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VSM measurement
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LLG simulationBy K. Machida
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Hy = 10 kOe 0 Oe Dot modeldivMdivMy
Saturation magnetization (Ms)800 emu/cm3Exchange field (A)110-6 erg/cm3Anisotropic constant (Ku)1000 erg/cm3Gyro magnetic constant)-1.76107 rad/(sOe)Damping constant0.2Easy axisY directionDot Size200 nm200 nm100 nmNumber of dot1Mesh size10 nm10 nm10 nm
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Hy = 10 kOeHy = 5 kOeHy = 3 kOeHy = 2 kOeHy = 1 kOeHy = 0 Oe
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AFM observationCircular dotsRectangular dotsAFM Line scan Surface roughness~10nm
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Rectangular dots VSM measurement
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Pattern variations for different scan directionScanning directionMFM images
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MFM image of 300nm x 100nm dot with a low-moment probe tipAFMMFM
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L=3m, d=200nm s=3mL=1.5 m, d=100nm s=1.5 mLds
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AFMMFMCROSS3 (200nm3000nm cross dots)
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Initial stateProbe-sampleAntiparallel 20kOeprobe-sampleParallel 20kOenmnm cross dots(wide scan)
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Initial stateProbe-sampleParallel 20kOeProbe-sample Parallel 20kOe200nm3000nm cross dots(narrow scan)
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MFM and AFM images of CROSS3
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Kerr microscope image
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InitializedProbe-sampleParallel 20kOeProbe-sample Antiparallel 20kOe100nm1500nm cross dots(wide scan)
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InitialProbe-sampleParallel 20kOeProbe-sampleParallel 20kOenmnm cross dots(narrow scan)
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LLG simulationCross-pattern model Hz = 20 kOe 0 Oe divMdivMz
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Hz = 1 kOeHz = 0 OeHz = 5 kOeHz = 10 kOeHz = 20 kOe
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Cross1(empty dots)1.5cmcamerascreen30
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Cross1(permalloy embedded)30
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90Cross3 (permalloy embedded)30
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Cross, no magnetic material embedded, H=0PinPoutSinPoutPinSoutSinSout
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Cross, permalloy embeddedH=2kOe appliedPinPout1st2nd3rdRepeated measurement
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Summary1mLLGMFMLLG
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Summary contdKerrSHGSHGMSHG
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ProposalMFMLLG1mMO-SNOMMO200nm100nm
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AcknowledgementCOE