Reduction of Offset Field in Top-Pinned MTJ With Synthetic Antiferromagnetic Free Layer

Author

Yoshida, Chikako ; Takenaga, Takashi ; Yamazaki, Yasuyuki ; Uehara, Hideyuki ; Noshiro, Hideyuki ; Tsunoda, Koji ; Iba, Yoshihisa ; Hatada, Akiyoshi ; Nakabayashi, Masaaki ; Takahashi, Asami ; Aoki, Masaki ; Sugii, Toshihiro

Author_Institution

Low-Power Electron. Assoc. & Project, Tsukuba, Japan

Volume

50

Issue

11

fYear

2014

fDate

Nov. 2014

Firstpage

1

Lastpage

4

Abstract

We found that the offset field (H_off) of a top-pinned magnetic tunnel junction (MTJ) with a CoPd/Ru/Ta/CoFeB-synthetic antiferromagnetic (SAF) free layer can be reduced by controlling the exchange coupling energy (J_ex) value. A micromagnetic simulation was used to derive the direct relation between the J_ex) of a CoPd/Ru/Ta/CoFeB-SAF free layer and the H_off) of a top-pinned MTJ with the SAF free layer. In addition, we found that the J_ex) value can be controlled by changing the thickness of the Ta spacer between the CoPd and CoFeB layers. As a result, we fabricated a top-pinned MTJ with a SAF free layer that eliminated the offset field and made it possible to improve the thermal stability.

Keywords

antiferromagnetic materials; boron alloys; cobalt alloys; exchange interactions (electron); interface magnetism; iron alloys; magnetic tunnelling; micromagnetics; palladium alloys; perpendicular magnetic anisotropy; ruthenium alloys; tantalum alloys; thermal stability; CoPd-Ru-Ta-CoFeB; exchange coupling energy; micromagnetic simulation; offset field reduction; spacer thickness; synthetic antiferromagnetic free layer; thermal stability; top-pinned magnetic tunnel junction; Couplings; Junctions; Magnetic tunneling; Perpendicular magnetic anisotropy; Stability criteria; Switches; Thermal stability; Offset field; perpendicular magnetic anisotropy (PMA); synthetic antiferromagnetic (SAF) free layer; top-pinned magnetic tunnel junction (MTJ);

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/TMAG.2014.2325965

Filename

6971334