Switching-Field Stabilization against Effects of High-Temperature Annealing in Magnetic Tunnel Junctions using Thermally Reliable NixFe100-x/Al-Oxide/Ta Free Layer
| Autor: | Yoshiyuki Fukumoto, Minoru Amano, Shuichi Tahara, Hiromitsu Hada, Hiroaki Yoda, Yoshiaki Asao, Norikazu Ohshima, Hideaki Numata, Kiyokazu Nagahara, Katsumi Suemitsu |
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| Rok vydání: | 2006 |
| Předmět: |
Magnetoresistive random-access memory
Materials science Physics and Astronomy (miscellaneous) Annealing (metallurgy) General Engineering Analytical chemistry Oxide General Physics and Astronomy Magnetostriction Tunnel magnetoresistance chemistry.chemical_compound Nuclear magnetic resonance chemistry Thermal Thermal stability Anisotropy |
| Zdroj: | Japanese Journal of Applied Physics. 45:3829-3834 |
| ISSN: | 1347-4065 0021-4922 |
| Popis: | We examined the effects of the capping layers of Ta, Al-oxide (AlO), and Ru on the magnetic properties of ultrathin (1–20 nm) NiFe free layers and investigated thermal degeneration of the switching field (Hsw) in magnetic tunnel junctions (MTJs) using these caps in the cell structure of magnetoresistive random access memory (MRAM). The magnetization reversal of the free layer was found to be sensitive to the capping layer that affected various magnetic anisotropies. For postannealing temperatures of up to 350 °C, the Hsw of a NiFe(2 nm)/AlO/Ta free layer was thermally stable, whereas that of conventional NiFe(3 nm)/Ta seriously deteriorated. This is because the AlO capping layer completely prevented the thermal interdiffusion between the NiFe and Ta layers even after annealing at 400 °C. Moreover, a free layer with a small magnetostriction reduced the influence of the stress-relaxation on the free layer caused by postannealing, which also resulted in a thermally stable Hsw in MTJs. |
| Databáze: | OpenAIRE |
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