Penetration depth and magnetic permeability calculations on GMI effect and comparison with measurements on CoFeB alloys

Coı̈sson, M.; Tiberto, P.; Vinai, F.; Tyagi, Parul; Modak, S. S.; Kane, S. N.

doi:10.1016/j.jmmm.2007.07.010

Cited by 10 publications

(4 citation statements)

References 23 publications

(28 reference statements)

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“…However, most MTJ research has focused on tunneling magnetoresistance (TMR). Additionally, most relevant investigations of magnetism have focused on high-frequency magnetic impedance (MI) [ 12 ]. Only a few have focused on low-frequency alternate-current magnetic susceptibility (χ ac ) and the optimal resonance frequency ( f res ).…”

Section: Introductionmentioning

confidence: 99%

Susceptibility of CoFeB/AlOx/Co Magnetic Tunnel Junctions to Low-Frequency Alternating Current

Chen

Chang

2013

Nanomaterials

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This investigation studies CoFeB/AlOx/Co magnetic tunneling junction (MTJ) in the magnetic field of a low-frequency alternating current, for various thicknesses of the barrier layer AlOx. The low-frequency alternate-current magnetic susceptibility (χac) and phase angle (θ) of the CoFeB/AlOx/Co MTJ are determined using an χac analyzer. The driving frequency ranges from 10 to 25,000 Hz. These multilayered MTJs are deposited on a silicon substrate using a DC and RF magnetron sputtering system. Barrier layer thicknesses are 22, 26, and 30 Å. The X-ray diffraction patterns (XRD) include a main peak at 2θ = 44.7° from hexagonal close-packed (HCP) Co with a highly (0002) textured structure, with AlOx and CoFeB as amorphous phases. The full width at half maximum (FWHM) of the Co(0002) peak, decreases as the AlOx thickness increases; revealing that the Co layer becomes more crystalline with increasing thickness. χac result demonstrates that the optimal resonance frequency (fres) that maximizes the χac value is 500 Hz. As the frequency increases to 1000 Hz, the susceptibility decreases rapidly. However, when the frequency increases over 1000 Hz, the susceptibility sharply declines, and almost closes to zero. The experimental results reveal that the mean optimal susceptibility is 1.87 at an AlOx barrier layer thickness of 30 Å because the Co(0002) texture induces magneto-anisotropy, which improves the indirect CoFeB and Co spin exchange-coupling strength and the χac value. The results concerning magnetism indicate that the magnetic characteristics are related to the crystallinity of Co.

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Section: Introductionmentioning

confidence: 99%

Susceptibility of CoFeB/AlOx/Co Magnetic Tunnel Junctions to Low-Frequency Alternating Current

Chen

Chang

2013

Nanomaterials

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“…Este tipo de perfil das amostras tratadas igual e sobre 1,4 A indica que existe uma anisotropia transversal nelas. Diferentemente do tratamento convencional, no tratamento por aquecimento Joule há uma importante indução de anisotropia transversal nas amostras [113].…”

Section: Resultados Gmiunclassified

“…A anisotropia gerada devido ao campo circular será de caráter transversal nas fitas. Resultados similares se observaram nos trabalhos onde se comenta que o método de tratamento térmico por aquecimento Joule é muito útil para a indução de anisotropia transversal em fitas [29,114,96,113], o que pode provocar uma melhora da resposta GMI.…”

Section: Resultados Gmiunclassified

“…Do mesmo modo no outro tipo de tratamento, a resposta GMI diminui depois de atingir um máximo na amostra tratada com corrente 1,6 A. Em amostras com correntes maiores de tratamento há um endurecimento magnético o que faz diminuir a resposta GMI [113]. Por outro lado, em relação à frequência, vê-se no primeiro gráfico que a resposta GMI aumenta com a frequência (figura 2.18 (a)).…”

Section: Resultados Gmiunclassified

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