Magnetic tunnel sensors with Co-Cu artificial antiferromagnetic (AAF) hard subsystem

Author

van den Berg, H.A.M. ; Altmann, J. ; Bär, L. ; Gieres, G. ; Kinder, R. ; Rupp, R. ; Vieth, M. ; Wecker, J.

Author_Institution

Siemens AG, Erlangen, Germany

Volume

35

Issue

5

fYear

1999

fDate

9/1/1999 12:00:00 AM

Firstpage

2892

Lastpage

2894

Abstract

Micron-size magnetic tunnel junctions are studied, in which the pinning of the hard magnetic reference layer is accomplished by the so-called Artificial Antiferromagnetic Subsystem (AAF). In the AAF, two Co layers are antiferromagnetically coupled by a 1 nm thick Cu layer, thus giving rise to stability windows larger than 2 kA/m for the AAF. Al ₂O₃-tunnel barriers of 1 and 1.5 nm Al thickness were put on top of the AAF and at its opposite surface Fe detection layers are located. The signal could be enhanced by a factor of two to 22% by inserting a 1 nm Co-coating between the barrier and the Fe. Thus sensors were realized with signals four times higher than for the GMR counterparts

Keywords

antiferromagnetic materials; cobalt; copper; giant magnetoresistance; magnetic multilayers; magnetic sensors; spin valves; tunnelling; 1 nm; Co-Cu; antiferromagnetically coupled layers; artificial antiferromagnetic hard system; hard magnetic reference layer pinning; magnetic stiffness; magnetic tunnel sensors; micron-size magnetic tunnel junctions; multilayers; position sensor; stability windows; tunnelling magnetoresistance; Antiferromagnetic materials; Argon; Couplings; Electrodes; Electrons; Geometry; Iron; Magnetic sensors; Magnetic tunneling; Sputtering;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.801016

Filename

801016