Title :
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
Abstract :
We found that the offset field (Hoff) 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 (Jex) value. A micromagnetic simulation was used to derive the direct relation between the Jex) of a CoPd/Ru/Ta/CoFeB-SAF free layer and the Hoff) of a top-pinned MTJ with the SAF free layer. In addition, we found that the Jex) 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);
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2014.2325965
