Characterization of a Nano-Oxide Layer in a Pseudo Spin Valve by Complex Magneto-Impedance Spectroscopy

Chien, Wei-Ming; Peng, T. Y.; Hsieh, L. C.; Lo, Chun-Wei; Yao, Y. D.

doi:10.1109/tmag.2006.879730

Cited by 7 publications

(6 citation statements)

References 6 publications

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“…3(b)] devices. With both the MTJ systems equivalent to the RC parallel circuit, their frequency dependence plots can be fitted using the Maxwell-Wagner capacitance model, 24,25,30,31 in which two RC networks are connected in series with one part being magnetic field dependent and the other being field independent. The field independent part can be removed by taking the difference of the impedances in the P and the AP states.…”

mentioning

confidence: 99%

Parallel-leaky capacitance equivalent circuit model for MgO magnetic tunnel junctions

Sahadevan¹,

Gopinadhan²,

Bhatia³

et al. 2012

Applied Physics Letters

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mentioning

confidence: 99%

Parallel-leaky capacitance equivalent circuit model for MgO magnetic tunnel junctions

Sahadevan¹,

Gopinadhan²,

Bhatia³

et al. 2012

Applied Physics Letters

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“…The capacitance is larger in the parallel state and smaller in the antiparallel state. [9][10][11] The magnetoimpedance MX shows maximum and minimum values of ±17 000% near a frequency of 17.7 MHz. This is due to the fact that the imaginary part of the impedance crosses zero at this resonance frequency.…”

mentioning

confidence: 99%

Enhancement and inverse behaviors of magnetoimpedance in a magnetotunneling junction by driving frequency

Chien

Hsieh

et al. 2006

Applied Physics Letters

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The magnetoimpedance effect was employed to study magnetotunneling junction (MTJ) with the structure of Ru(5nm)∕Cu(10nm)∕Ru(5nm)∕IrMn(10nm)∕CoFeB(4nm)∕Al(1.2nm)-oxide∕CoFeB(4nm)∕Ru(5nm). A huge change of more than ±17000% was observed in the imaginary part of the impedance between the magnetically parallel and antiparallel states of the MTJ. The inverse behavior of the magnetoimpedance (MI) loop occurs beyond 21.1MHz; however, the normal MI at low frequency and the inverse MI at high frequency exhibit the same magnetization reversal as checked by the Kerr effect. The reversal in MI was due to the dominance of magnetocapacitance at high frequency.

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“…The oxidative thickness is in proportion to f roll and in reverse proportion to C eff . 6 The result of f roll , which increased as annealing temperature increased to 140°C, indicated that the oxidative thickness of Co layer was increasing. This increase in thickness caused the resistance to increase and the dc MR ratio to decrease slightly.…”

Section: Resultsmentioning

confidence: 98%

“…4 In a nonmetallic system, the impedance ͑Z͒ is comprised of resistance ͑R͒, inductance ͑L͒, and capacitance ͑C͒; therefore, equivalent circuit theory can be used to analyze the ac behavior. 5 In our previous work, 6 we utilized the impedance technique to investigate the NOL behavior in PSV. In this study, we extend the impedance technique to report on the frequency response features of the magnetoimpedance ͑MI͒ behavior of PSV in more detail and use impedance spectroscopy to conduct nondestructive analysis of a PSV with a NOL after annealing.…”

Section: Introductionmentioning

confidence: 99%

Magnetoimpedance behavior and its equivalent circuit analysis of Co/Cu/Co/Py pseudo-spin-valve with a nano-oxide layer

Chien

Yao

et al. 2009

Journal of Applied Physics

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Magnetoimpedance behaviors and thermal effects of a Co/Cu/Co/Py pseudo-spin-valve (PSV) with a nano-oxide layer (NOL) were studied. The PSV can be regarded as a combination of resistances, inductances, and capacitances. In addition, equivalent circuit theory can be used to analyze the ac behavior of this system. The imaginary part of the magnetoimpedance (magnetoreactance) ratio is more than 1700% at the resonance frequency (f(r))=476 kHz at room temperature (R(T)). The dc magnetoresistance (MR) ratio decreases as the annealing temperature increases because the NOL is formed at the interface between the spacer and the magnetic layer. The NOL deteriorates the differential spin scattering and reduces the dc MR ratio. Impedance spectroscopy was utilized to analyze the capacitance effect from NOL after annealing. The effective capacitance of the PSV was 21.8 nF at R(T) and changed to 11.8 nF after annealing at 200 degrees C. The useful equivalent capacitor circuit not only is a nondestructive measurement technology but can also explain the experimental results and prove the formation of the NOL

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Characterization of a Nano-Oxide Layer in a Pseudo Spin Valve by Complex Magneto-Impedance Spectroscopy

Cited by 7 publications

References 6 publications

Parallel-leaky capacitance equivalent circuit model for MgO magnetic tunnel junctions

Parallel-leaky capacitance equivalent circuit model for MgO magnetic tunnel junctions

Enhancement and inverse behaviors of magnetoimpedance in a magnetotunneling junction by driving frequency

Magnetoimpedance behavior and its equivalent circuit analysis of Co/Cu/Co/Py pseudo-spin-valve with a nano-oxide layer

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