Dr. Vadym Zayetsv.zayets(at)gmail.com |
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more Chapters on this topic:IntroductionTransport Eqs.Spin Proximity/ Spin InjectionSpin DetectionBoltzmann Eqs.Band currentScattering currentMean-free pathCurrent near InterfaceOrdinary Hall effectAnomalous Hall effect, AMR effectSpin-Orbit interactionSpin Hall effectNon-local Spin DetectionLandau -Lifshitz equationExchange interactionsp-d exchange interactionCoercive fieldPerpendicular magnetic anisotropy (PMA)Voltage- controlled magnetism (VCMA effect)All-metal transistorSpin-orbit torque (SO torque)What is a hole?spin polarizationCharge accumulationMgO-based MTJMagneto-opticsSpin vs Orbital momentWhat is the Spin?model comparisonQuestions & AnswersEB nanotechnologyReticle 11
more Chapters on this topic:IntroductionTransport Eqs.Spin Proximity/ Spin InjectionSpin DetectionBoltzmann Eqs.Band currentScattering currentMean-free pathCurrent near InterfaceOrdinary Hall effectAnomalous Hall effect, AMR effectSpin-Orbit interactionSpin Hall effectNon-local Spin DetectionLandau -Lifshitz equationExchange interactionsp-d exchange interactionCoercive fieldPerpendicular magnetic anisotropy (PMA)Voltage- controlled magnetism (VCMA effect)All-metal transistorSpin-orbit torque (SO torque)What is a hole?spin polarizationCharge accumulationMgO-based MTJMagneto-opticsSpin vs Orbital momentWhat is the Spin?model comparisonQuestions & AnswersEB nanotechnologyReticle 11
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Volt 55 Ta(5 nm)/ FeB(0.9 nm)/ MgO(6 nm)/ Ta(1 nm)/ Ru(5 nm)Measurement of magnetic and magneto- transport properties of nanomagnets. Measurement data.Abstract:High- precision, high- reproducibility, high- repeatability measurement of magnetic and magneto- transport properties of ferromagnetic nanomagnets using the Hall effectHigh-precision measurement of effect of spin-orbit torque (SOT effect): Dependence of magnetic and magneto- transport properties on electrical currentHigh-precision measurement of effect of voltage-controlled magnetic anisotropy (VCMA effect): Dependence of magnetic and magneto- transport properties on a gate voltageMeasurements(measurement 1) Measurement of Hall angle vs external perpendicular magnetic field
(1.2) Spin-orbit torque: Measurement of dependence of Hall angle, Anomalous Hall effect (AHE), Inverse Spin Hall effect on current magnitude and polarity. (1.3) VCMA: Measurement of dependence of Hall angle, Anomalous Hall effect (AHE), Inverse Spin Hall effect on gate voltage (measurement 2) Measurement of anisotropy field vs external perpendicular magnetic field (2.1) Measurement of PMA & Anisotropy field (2.2) Spin-orbit torque: ""Field- like torque" ""Damp- like torque". Measurement of dependence of PMA on the electrical current . (2.3) VCMA: ""Field- like torque" ""Damp- like torque". Measurement of dependence of PMA on gate voltage. (measurement 3) Measurement of magnetization switching under external perpendicular magnetic field (3.1) Measurement of coercive field HC, retention time, size of nucleation domain, parameter delta Δ (3.2) Spin-orbit torque: Current dependence of magnetization switching parameters. (3.3) VCMA: dependence of magnetization switching parameters on gate voltage.
Details of Measurement Methods are here
Volt 55 Ta(5 nm)/ FeB(0.9 nm)/ MgO(6 nm)/ Ta(1 nm)/ Ru(5 nm)
fabrication: EB only, 18/01/30 day3 MgO 220C/360C Raw data Volt55.zip (.dat files and origin 9 files) (7zip (free) download is here)Conductivity: 0.028-0.038 S/m2 Anisotropy field Hanis =4 kGauss-11 kGauss Coercive field = 150 Oe-225 Oe; (a few: 400 Oe,90 Oe) Hall angle measured=200- 650 mdeg Intrinsic Hall angle of FeB= 1311 - 4261 mdeg; Gap region etched: FeB is fully (partiality) etched, stopped at Ta/FeB interface (in middle of FeCoB)
magnetization- switching parameters:
retention time τret (gate): free77-> 1028 s; free74-> 1028 s; ud17-> 1011 s; ud44-> 1019 s; ud10-> 105 s; (gap): free77-> 109 s; free74-> 1011 s; ud17-> 104 s; ud44-> 104 s; ud10-> 1011 s; size of nucleation domain: (gate): free77-> 90 nm; free74-> 90 nm; ud17-> 60 nm; ud44-> 45 nm; ud10-> 35 nm; (gap): free77-> 45 nm; free74-> 55 nm; ud17-> 25 nm; ud44-> 45 nm; ud10-> 55 nm; coercive field Hc: (gate): free77-> 150 Oe; free74-> 150 Oe; ud17-> 150 Oe; ud44-> 400 Oe; ud10-> 225 Oe; (gap): free77-> 180 Oe; free74-> 150 Oe; ud17-> 400 Oe; ud44-> 100 Oe; ud10-> 150 Oe; parameter Δ : (gate): free77-> 600; free74-> 800; ud17-> 330; ud44->190; ud10->150; (gap): free77-> 200; free74-> 300; ud17-> 40; ud44->90; ud10->150;
sizes of nanomagnets & conductivity σfabricated 180320(free 74): wire width: 1000 nm; nanomagnet length:2000 nm; σ = 0.032 S/m2 (free 77): wire width: 400 nm; nanomagnet length: 200 nm; σ = 0.038 S/m2 (ud 10 ): wire width: 1000 nm; nanomagnet length: 500 nm; σ = 0.028 S/m2 (ud 17): wire width: 400 nm; nanomagnet length: 200 nm; σ = 0.035 S/m2 (ud 19): wire width: 400 nm; nanomagnet length: 500 nm; σ = 0.034 S/m2 (ud 44): wire width: 1000 nm; nanomagnet length: 2000 nm; σ = 0.056S/m2 ? error? (ud 40): wire width: 1000 nm; nanomagnet length: 5000 nm; σ = 0.028 S/m2 note: free -> without a gate electrode; up -> with a gate electrode
Since the nanowire is double- layer, which consists of Ta and FeB layer, the Hall angle αHall, FeB in FeB can be calculated from measured Hall angle αHall, measured (See here) as where tFeB, tTa, σFeB,σTa are thicknesses and conductivities of FeB and Ta metals.
kdouble=6.5556
(measurement 1) Measurement of Hall angle vs external perpendicular magnetic field Hz
Fitting of Hall angleThe Hall angle αHall , its 1st derivation ∂αHall/∂Hz and its 2d derivation ∂2αHall/∂Hz2 is simultaneously fitted by equation (See here) where αOHE is Hall angle of Ordinary Hall effect, αAHE is Hall angle of Anomalous Hall effect and where αISHE is Hall angle of Inverse Spin Hall effect There is an ambiguity for αISHE and αAHE, which depends on unknown spin polarization sp where sp is the spin polarization of conduction electrons, αAHE,0.5 is αAHE at sp=0.5, αISHE,0.5 is αISHE at sp=0.5 result of fitting:sample:( free74 gate) αISHE,0.5= 261 mdeg; αAHE,0.5= 2257 mdeg; αOHE=0.2 mdeg/kG; Hp=10.31 kG; sample:( free77 gate) αISHE,0.5= 537 mdeg; αAHE,0.5= 2096 mdeg; αOHE=0.2 mdeg/kG; Hp=6.48 kG; sample:(ud10) αISHE,0.5= 180.6 mdeg; αAHE,0.5= 1886 mdeg; αOHE=0.2 mdeg/kG; Hp=6.15 kG; sample:(ud17) αISHE,0.5= 200 mdeg; αAHE,0.5= 2722 mdeg; αOHE=0.2 mdeg/kG; Hp=5.05 kG; sample:(ud19) αISHE,0.5= 391 mdeg; αAHE,0.5= 900.5 mdeg; αOHE=0.2 mdeg/kG; Hp=5.0 kG; sample:(ud40) αISHE,0.5= 323.8 mdeg; αAHE,0.5= 1141 mdeg; αOHE=0.2 mdeg/kG; Hp=7.25 kG; sample:(ud44) αISHE,0.5= 610 mdeg; αAHE,0.5= 3690 mdeg; αOHE=0.2 mdeg/kG; Hp=9.5 kG; sample:(ud49) αISHE,0.5= 324 mdeg; αAHE,0.5= 804.1 mdeg; αOHE=0.2 mdeg/kG; Hp=7.29 kG;
AHE & ISHE vs current & current polarity. SOT effectMeasurement 1. Dependence of Anomalous Hall effect (AHE) & Inverse Spin Hall effect (ISHE) on current and current polarity. Effect of Spin-Orbit Torque (SOT)
Features(temparature) dependence on current magnitude(AHE vs I2 ): strong 6-12% decrease at current of 50 mA/ μm2; (fig.4a) (ISHE vs I2 ):strong, 0.4 mdeg/kG decrease at 50 mA/ μm2 (fig.4b) (Spin- orbit torque) dependence on current polarity(AHE(I)-AHE(-I)):strong 0.6-1.2 % slope: negative (all large, positive for small) ; saturation: at 25 mA/ μm2; (fig.4c) (ISHE(I)-ISHE(-I)): moderate (~0.2-0.3 mdeg/kG) (fig.4d)
AHE & ISHE vs gate voltage. VCMA effectMeasurement 1. Dependence of Anomalous Hall effect (AHE) & Inverse Spin Hall effect (ISHE) on gate voltage. Effect of Voltage-Controlled Magnetic Anisotropy (VCMA)
Features
dependence on gate voltage(AHE vs Vgate ): weak 0.5 % ; slope: unclear (ISHE vs Vgate ): weak 0.07 mdeg/kG; slope: unclear (measurement 2) Measurement of anisotropy field vs external perpendicular magnetic field Hzdetails about measurement method is here and here
Spin-orbit torque vs PMA
VCMA vs PMA
(measurement 3) Measurement of magnetization switching under external perpendicular magnetic field Hz
VCMA vs Coercive field
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