High-temperature operations of rotation angle sensors with spin-valve-type magnetic tunnel junctions

Author

Takenaga, Takashi ; Sadeh, Beysen ; Kuroiwa, Takeharu ; Kobayashi, Hiroshi ; Oomori, Tatsuo

Author_Institution

Adv. Technol. R&D Center, Mitsubishi Electr. Corp., Hyogo, Japan

Volume

41

Issue

10

fYear

2005

Firstpage

3628

Lastpage

3630

Abstract

Direction detection of a magnetic field by spin-valve-type magnetic tunnel junction (MTJ) has been investigated at temperatures ranging from room to 150°C, concentrating on the magnetic property of the pinned layer. Angular dependencies of resistance curves show that detection errors from cosine curve increase with rising temperatures in MTJ with the IrMn/CoFe pinned layer. Measurements of the magnetization curves of the pinned layer found that detection errors are caused by rotation of the pinned layer magnetization. Direction detection of a magnetic field by MTJ with a IrMn/CoFe/Ru/CoFe of synthetic antiferromagnetic (SyAF) pinned layer, in which magnetizations of two CoFe layers nearly cancel each other, was also investigated. We confirmed that the pinned layer of SyAF structure in MTJ effectively reduces the dependence of detection errors on temperature.

Keywords

antiferromagnetic materials; cobalt alloys; iridium alloys; iron alloys; magnetic sensors; magnetic tunnelling; magnetisation; manganese alloys; ruthenium alloys; spin valves; synthetic metals; IrMn-CoFeRu-CoFe; high-temperature operation; magnetic field detection; magnetic properties; magnetic sensors; magnetization curve measurement; pinned layer magnetization; rotation angle sensors; spin-valve-type magnetic tunnel junctions; synthetic antiferromagnetic pinned layers; Electrical resistance measurement; Magnetic field measurement; Magnetic fields; Magnetic properties; Magnetic sensors; Magnetic tunneling; Magnetization; Temperature dependence; Temperature distribution; Temperature sensors; Magnetic sensors; magnetic tunnel junctions; spin valves; synthetic antiferromagnet;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/TMAG.2005.855171

Filename

1519392