Photoconductance in magnetic tunnel junctions

Author

Koller, P.H.P. ; Vanhelmont, F.W.M. ; Coehoorn, R. ; de Jonge, W.J.M.

Author_Institution

Dept. of Appl. Phys., Eindhoven Univ. of Technol., Netherlands

Volume

38

Issue

5

fYear

2002

fDate

9/1/2002 12:00:00 AM

Firstpage

2712

Lastpage

2714

Abstract

The photoconductance of magnetic tunnel junctions has been studied in order to obtain directly determined values of the tunnel barrier height. Experiments for different types of junctions show that the presence of an aluminum layer close to the oxide barrier is crucial for the observation of a large photocurrent. For Ni₈₀Fe₂₀-based magnetic tunnel junctions, the effective barrier height increases with increasing magnetic layer thickness between the aluminum source layer and the aluminum oxide barrier. This trend is also visible in the barrier height determined from a Simmons fit to the current-voltage characteristics.

Keywords

MIM structures; Permalloy; giant magnetoresistance; hot carriers; magnetic multilayers; photoconductivity; tunnelling; Fowler equation; Ni₈₀Fe₂₀; Simmons fit; current-voltage characteristics; effective barrier height; large photocurrent; magnetic layer thickness; magnetic tunnel junctions; magnetoconductance; photoconductance; tunnel barrier height; Aluminum; Electrodes; Electrons; Geometry; Iron; Magnetic tunneling; Oxidation; Photoconducting materials; Photoconductivity; Plasma materials processing;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/TMAG.2002.803171

Filename

1042327