Oxidation process of AlOx-based magnetic tunnel junctions studied by photoconductance

P.H.P. Koller; F.W.M. Vanhelmont; H. Boeve; P.G.E. Lumens; W.J.M. Jonge, de

doi:10.1063/1.1555317

Oxidation process of AlOx-based magnetic tunnel junctions studied by photoconductance

P.H.P. Koller, F.W.M. Vanhelmont, H. Boeve, P.G.E. Lumens, W.J.M. Jonge, de

Physics of Nanostructures

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Abstract

The oxidation process of Co/AlOx/Co magnetic tunnel junctions has been investigated by photoconductance, in addition to traditional transport measurements. The shape of the photoconductance curves is explained within the framework of a simple qualitative model, assuming an oxidation time dependent imbalance of the incident forward and reverse hot electron fluxes, as well as inelastic scattering processes in the oxide. Due to the large sensitivity of the technique, the presence of unoxidized Al beneath the barrier layer can be monitored very accurately. The disappearance of a negative contribution to the photocurrent indicates the complete oxidation of the barrier layer, which coincides with the maximum magnetoresistance. From a Fowler analysis, the barrier height is determined as a function of oxidation time. The observed disagreement of the effective barrier heights determined by this technique and those found by Simmons fits demonstrates the added value of photoconductance studies.

Original language	English
Pages (from-to)	8549-8551
Journal	Journal of Applied Physics
Volume	93
Issue number	10
DOIs	https://doi.org/10.1063/1.1555317
Publication status	Published - 2003

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title = "Oxidation process of AlOx-based magnetic tunnel junctions studied by photoconductance",

abstract = "The oxidation process of Co/AlOx/Co magnetic tunnel junctions has been investigated by photoconductance, in addition to traditional transport measurements. The shape of the photoconductance curves is explained within the framework of a simple qualitative model, assuming an oxidation time dependent imbalance of the incident forward and reverse hot electron fluxes, as well as inelastic scattering processes in the oxide. Due to the large sensitivity of the technique, the presence of unoxidized Al beneath the barrier layer can be monitored very accurately. The disappearance of a negative contribution to the photocurrent indicates the complete oxidation of the barrier layer, which coincides with the maximum magnetoresistance. From a Fowler analysis, the barrier height is determined as a function of oxidation time. The observed disagreement of the effective barrier heights determined by this technique and those found by Simmons fits demonstrates the added value of photoconductance studies.",

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T1 - Oxidation process of AlOx-based magnetic tunnel junctions studied by photoconductance

AU - Koller, P.H.P.

AU - Vanhelmont, F.W.M.

AU - Boeve, H.

AU - Lumens, P.G.E.

AU - Jonge, de, W.J.M.

PY - 2003

Y1 - 2003

N2 - The oxidation process of Co/AlOx/Co magnetic tunnel junctions has been investigated by photoconductance, in addition to traditional transport measurements. The shape of the photoconductance curves is explained within the framework of a simple qualitative model, assuming an oxidation time dependent imbalance of the incident forward and reverse hot electron fluxes, as well as inelastic scattering processes in the oxide. Due to the large sensitivity of the technique, the presence of unoxidized Al beneath the barrier layer can be monitored very accurately. The disappearance of a negative contribution to the photocurrent indicates the complete oxidation of the barrier layer, which coincides with the maximum magnetoresistance. From a Fowler analysis, the barrier height is determined as a function of oxidation time. The observed disagreement of the effective barrier heights determined by this technique and those found by Simmons fits demonstrates the added value of photoconductance studies.

AB - The oxidation process of Co/AlOx/Co magnetic tunnel junctions has been investigated by photoconductance, in addition to traditional transport measurements. The shape of the photoconductance curves is explained within the framework of a simple qualitative model, assuming an oxidation time dependent imbalance of the incident forward and reverse hot electron fluxes, as well as inelastic scattering processes in the oxide. Due to the large sensitivity of the technique, the presence of unoxidized Al beneath the barrier layer can be monitored very accurately. The disappearance of a negative contribution to the photocurrent indicates the complete oxidation of the barrier layer, which coincides with the maximum magnetoresistance. From a Fowler analysis, the barrier height is determined as a function of oxidation time. The observed disagreement of the effective barrier heights determined by this technique and those found by Simmons fits demonstrates the added value of photoconductance studies.

U2 - 10.1063/1.1555317

DO - 10.1063/1.1555317

M3 - Article

SN - 0021-8979

VL - 93

SP - 8549

EP - 8551

JO - Journal of Applied Physics

JF - Journal of Applied Physics

IS - 10

ER -

Oxidation process of AlOx-based magnetic tunnel junctions studied by photoconductance

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