60% magnetoresistance at room temperature in Co–Fe/Al–O/Co–Fe tunnel junctions oxidized with Kr–O2 plasma
60% magnetoresistance at room temperature in Co–Fe/Al–O/Co–Fe tunnel junctions oxidized with Kr–O2 plasma
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DOI：
10.1063/1.1475363
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发表时间：
2002-04
影响因子：
4
通讯作者：
M. Tsunoda;K. Nishikawa;S. Ogata;M. Takahashi
中科院分区：
文献类型：
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作者：
M. Tsunoda;K. Nishikawa;S. Ogata;M. Takahashi
研究了等离子体氧化金属Al层时混合惰性气体对磁性隧道结（MTJ）隧道磁阻（TMR）的影响，Ta 50 A/Cu 200 A/Ta 200 A/Ni-Fe 50 A/Cu 50 A/Mn75Ir25 100 A/Co70Fe30 25 A/Al-O/Co70Fe30 25 A/Ni-Fe 100 A/Cu 200 A/Ta 50 A。采用Kr-O_2等离子体，在室温下对结进行300 °C退火后，获得了58.8%的TMR比，而采用普通Ar-O_2等离子体制备的MTJ的TMR比保持在48.6%。通过使用Kr-O2等离子体的Al层的更快的氧化速率是防止Al层的过度氧化（其使下层铁磁电极的表面去极化）和实现大的磁阻的可能原因。
The influence of the mixed inert gas species for plasma oxidization process of a metallic Al layer on the tunnel magnetoresistance (TMR) was investigated for a magnetic tunnel junction (MTJ), Ta 50 A/Cu 200 A/Ta 200 A/Ni–Fe 50 A/Cu 50 A/Mn75Ir25 100 A/Co70Fe30 25 A/Al–O/Co70Fe30 25 A/Ni–Fe 100 A/Cu 200 A/Ta 50 A. Using Kr–O2 plasma, a 58.8% of TMR ratio was obtained at room temperature after annealing the junction at 300 °C, while the achieved TMR ratio of the MTJ fabricated with usual Ar–O2 plasma remained 48.6%. A faster oxidization rate of the Al layer by using Kr–O2 plasma is a possible cause to prevent the over oxidization of the Al layer, which depolarizes the surface of the underlaid ferromagnetic electrode, and to realize a large magnetoresistance.