Abstract
We report an effect of field cooling direction on the magnetoresistance of ring-shaped magnetic tunnel junctions consisting of Ta 5/Cu 20/ Ta 5/NiFe 2/Cu 5/MnIr 10/CoFe 4/Al-N 1.5/CoFe 4/NiFe 20/Ta 5-cap (thickness in nm). The magnetoresistances were both enhanced, in comparison to the as-fabricated ring device, with field-cooling directions applied in the film plane as well as perpendicular to the film plane but with greater increase in the case of perpendicular-field-cooled. Many cycles of planar- and perpendicular-field- cooled alternately gave the same results. The greater enhancement of magnetoresistance is shown to be due to the formation of an onion like magnetization configuration in the pinned layer after perpendicular-field- cooled, resulting in a better relative magnetization alignment between the pinned layer and the free layer in the minor loop region. Magnetic force microscopy (MFM) was undertaken to reveal the uniform and onion like magnetization configurations in the pinned layer of ring devices with the same dimensions, but with layer structures of Ta 5/NiFe 2/Cu 5/MnIr 10/CoFe 4/Cu 1/Ta 1 (thickness in nm) for the planar- and perpendicular-field-cooled, respectively. In addition, size-dependent behavior was explored and the results show that the formation of onion like magnetization after perpendicularfield- cooled is associated with the strong shape anisotropy in the narrower linewidths of ring devices.
| Original language | English |
|---|---|
| Pages (from-to) | 530011-530014 |
| Number of pages | 4 |
| Journal | Japanese Journal of Applied Physics |
| Volume | 48 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - 2009 May 1 |
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All Science Journal Classification (ASJC) codes
- Engineering(all)
- Physics and Astronomy(all)
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Effects of field cooling direction on magnetoresistance of exchange-biased magnetic tunnel junction rings. / Chen, Che Chin; Kuo, Cheng Yi; Horng, Lance; Isogami, Shinji; Tsunoda, Masakiyo; Takahashi, Migaku; Wu, Jong-Ching.
In: Japanese Journal of Applied Physics, Vol. 48, No. 5, 01.05.2009, p. 530011-530014.Research output: Contribution to journal › Article
TY - JOUR
T1 - Effects of field cooling direction on magnetoresistance of exchange-biased magnetic tunnel junction rings
AU - Chen, Che Chin
AU - Kuo, Cheng Yi
AU - Horng, Lance
AU - Isogami, Shinji
AU - Tsunoda, Masakiyo
AU - Takahashi, Migaku
AU - Wu, Jong-Ching
PY - 2009/5/1
Y1 - 2009/5/1
N2 - We report an effect of field cooling direction on the magnetoresistance of ring-shaped magnetic tunnel junctions consisting of Ta 5/Cu 20/ Ta 5/NiFe 2/Cu 5/MnIr 10/CoFe 4/Al-N 1.5/CoFe 4/NiFe 20/Ta 5-cap (thickness in nm). The magnetoresistances were both enhanced, in comparison to the as-fabricated ring device, with field-cooling directions applied in the film plane as well as perpendicular to the film plane but with greater increase in the case of perpendicular-field-cooled. Many cycles of planar- and perpendicular-field- cooled alternately gave the same results. The greater enhancement of magnetoresistance is shown to be due to the formation of an onion like magnetization configuration in the pinned layer after perpendicular-field- cooled, resulting in a better relative magnetization alignment between the pinned layer and the free layer in the minor loop region. Magnetic force microscopy (MFM) was undertaken to reveal the uniform and onion like magnetization configurations in the pinned layer of ring devices with the same dimensions, but with layer structures of Ta 5/NiFe 2/Cu 5/MnIr 10/CoFe 4/Cu 1/Ta 1 (thickness in nm) for the planar- and perpendicular-field-cooled, respectively. In addition, size-dependent behavior was explored and the results show that the formation of onion like magnetization after perpendicularfield- cooled is associated with the strong shape anisotropy in the narrower linewidths of ring devices.
AB - We report an effect of field cooling direction on the magnetoresistance of ring-shaped magnetic tunnel junctions consisting of Ta 5/Cu 20/ Ta 5/NiFe 2/Cu 5/MnIr 10/CoFe 4/Al-N 1.5/CoFe 4/NiFe 20/Ta 5-cap (thickness in nm). The magnetoresistances were both enhanced, in comparison to the as-fabricated ring device, with field-cooling directions applied in the film plane as well as perpendicular to the film plane but with greater increase in the case of perpendicular-field-cooled. Many cycles of planar- and perpendicular-field- cooled alternately gave the same results. The greater enhancement of magnetoresistance is shown to be due to the formation of an onion like magnetization configuration in the pinned layer after perpendicular-field- cooled, resulting in a better relative magnetization alignment between the pinned layer and the free layer in the minor loop region. Magnetic force microscopy (MFM) was undertaken to reveal the uniform and onion like magnetization configurations in the pinned layer of ring devices with the same dimensions, but with layer structures of Ta 5/NiFe 2/Cu 5/MnIr 10/CoFe 4/Cu 1/Ta 1 (thickness in nm) for the planar- and perpendicular-field-cooled, respectively. In addition, size-dependent behavior was explored and the results show that the formation of onion like magnetization after perpendicularfield- cooled is associated with the strong shape anisotropy in the narrower linewidths of ring devices.
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U2 - 10.1143/JJAP.48.053001
DO - 10.1143/JJAP.48.053001
M3 - Article
AN - SCOPUS:68349119259
VL - 48
SP - 530011
EP - 530014
JO - Japanese Journal of Applied Physics
JF - Japanese Journal of Applied Physics
SN - 0021-4922
IS - 5
ER -