Current distribution effects in magnetoresistive tunnel junctions

Veerdonk, van de Rjm René; Nowak, Janusz; Meservey, R.; Moodera, J. S.; Jonge, de Wjm Wim

doi:10.1063/1.120149

Cited by 87 publications

(27 citation statements)

References 8 publications

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“…As early as 1968 breakdown fields of plasma oxidized Al films for capacitors with varying thicknesses were reported. 2 An E bd of 1ϫ10 9 V/m for a 1.5 nm film was found, which is comparable to our values of V bd ϭ1 V in a 1.0-2.0 nm barrier. In the past three decades, the mechanism of breakdown has been intensively investigated for MOS capacitors.…”

Section: ͓S0003-6951͑98͒04542-2͔supporting

confidence: 75%

“…The resistance of these junctions decreased by only 50% when the bottom electrode width increased from 50 to 200 m, suggesting a nonuniform current density distribution across the junction area. This cannot be the result of a geometrical artefact, 9 since the junction resistance (ϳ100 k⍀) is much larger than the sheet resistances of the electrodes (ϳ10 ⍀). A lower resistivity at the edges can be a possible explanation.…”

Section: ͑3͒mentioning

confidence: 99%

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Dielectric breakdown of ferromagnetic tunnel junctions

Oepts

Verhagen

Jonge

et al. 1998

Applied Physics Letters

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The time-dependent dielectric breakdown of Co/Al2O3/Co(-Fe) magnetic tunnel junctions is investigated. At voltages larger than 1.2 V, almost immediate breakdown of the junction is observed, leading to a decreased (magneto)resistance. The shorts, which are local hot spots, were visualized by making use of a liquid crystal film on top of the junction. The breakdown voltages of a series of nominally identical tunnel junctions measured in a voltage-ramp experiment are shown to increase with increasing ramp speed. The results are analyzed in the framework of several models for the voltage dependent breakdown probability.

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Section: ͓S0003-6951͑98͒04542-2͔supporting

confidence: 75%

Section: ͑3͒mentioning

confidence: 99%

Dielectric breakdown of ferromagnetic tunnel junctions

Oepts

Verhagen

Jonge

et al. 1998

Applied Physics Letters

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“…In a real device, the distribution of the current across the interface depends on the relative magnitude of the interface resistance to the electrode resistance [33]. When the interface resistance is much larger than the electrode resistance as in tunnel junctions, the current distribution is uniform in the contact area [34], which validates the assumption of uniform interface current.…”

Section: Spin Injection and Spin Accumulationmentioning

confidence: 58%

Spin current, spin accumulation and spin Hall effect

Takahashi

Maekawa

2008

Science and Technology of Advanced Materials

172

136

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Nonlocal spin transport in nanostructured devices with ferromagnetic injector (F1) and detector (F2) electrodes connected to a normal conductor (N) is studied. We reveal how the spin transport depends on interface resistance, electrode resistance, spin polarization and spin diffusion length, and obtain the conditions for efficient spin injection, spin accumulation and spin current in the device. It is demonstrated that the spin Hall effect is caused by spin-orbit scattering in nonmagnetic conductors and gives rise to the conversion between spin and charge currents in a nonlocal device. A method of evaluating spin-orbit coupling in nonmagnetic metals is proposed.

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“…In the case of a square junction a negative resistance is measured when the junction resistance is less than one fourth of the lead sheet resistance. 11 Stress measurements at a constant voltage of 1 V showed a time to breakdown of the order of minutes. Junctions grown in the same run and having the same junction area showed a comparable lifetime when biased at the same V bias .…”

Section: Resultsmentioning

confidence: 99%

Analysis of breakdown in ferromagnetic tunnel junctions

Oepts

Verhagen

Coehoorn

et al. 1999

Journal of Applied Physics

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Due to their very thin tunnel barrier layer, magnetic tunnel junctions show dielectric breakdown at voltages of the order of 1 V. At the moment of breakdown, a highly conductive short is formed in the barrier and is visible as a hot spot. The breakdown effect is investigated by means of voltage ramp experiments on a series of nominally identical Co/Al 2 O 3 /Co tunnel junctions. The results are described in terms of a voltage dependent breakdown probability, and are further analyzed within the framework of a general model for the breakdown probability in dielectric materials, within which it is assumed that at any time the breakdown probability is independent of the ͑possibly time-dependent͒ voltage that has been previously applied. The experimental data can be described by several specific forms of the voltage breakdown probability function. A comparison with the models commonly used for describing thin film SiO 2 breakdown is given, as well as suggestions for future experiments.

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Current distribution effects in magnetoresistive tunnel junctions

Abstract: Effect of microstructure on the magnetoresistive properties of NiFe/Co(CoFe)/Al(Ta)-oxide/Co(CoFe) tunnel junctions

Cited by 87 publications

References 8 publications

Dielectric breakdown of ferromagnetic tunnel junctions

Dielectric breakdown of ferromagnetic tunnel junctions

Spin current, spin accumulation and spin Hall effect

Analysis of breakdown in ferromagnetic tunnel junctions

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