Half-metallic electronic structure of Co2MnSi electrodes in fully epitaxial Co2MnSi/MgO/Co2MnSi magnetic tunnel junctions investigated by tunneling spectroscopy (invited)
Half-metallic electronic structure of Co2MnSi electrodes in fully epitaxial Co2MnSi/MgO/Co2MnSi magnetic tunnel junctions investigated by tunneling spectroscopy (invited)
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DOI：
10.1063/1.3089732
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发表时间：
2009-03
影响因子：
3.2
通讯作者：
T. Ishikawa;Naoki Itabashi;T. Taira;K. Matsuda;T. Uemura;Masafumi Yamamoto
中科院分区：
文献类型：
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作者：
T. Ishikawa;Naoki Itabashi;T. Taira;K. Matsuda;T. Uemura;Masafumi Yamamoto
我们利用隧道光谱研究了Co2 MnSi（CMS）电极面对MgO势垒时的自旋相关电子结构，以及完全外延CMS/MgO/CMS磁性隧道结（MTJ）中的关键隧道机制，该结在室温下显示出高达182%的隧道磁电阻率，在4.2K下显示出高达705%的隧道磁电阻率。因此，我们开发了一个模型的CMS电极的自旋相关的电子结构和隧道模型，可以一致地解释所观察到的隧道光谱。在这里，我们表明，下（上）CMS电极具有0.40 eV（0.32 eV）的半金属间隙与费米能级（EF）的中间附近的半金属间隙的下部和上部CMS电极。此外，我们发现了强有力的证据，在界面区域的CMS电极面临的MgO障碍，以及在上CMS电极的体区域的残留状态的证据，在这两种情况下，少数自旋周围EF的界面状态的存在，我们表明，界面状态起着关键的…
We used tunneling spectroscopy to examine the spin-dependent electronic structure of Co2MnSi (CMS) electrodes facing a MgO barrier and the key tunneling mechanism in fully epitaxial CMS/MgO/CMS magnetic tunnel junctions (MTJs) that showed high tunnel magnetoresistance ratios up to 182% at room temperature and 705% at 4.2 K. Consequently, we developed a model of the spin-dependent electronic structure for CMS electrodes and a tunneling model that can consistently explain the observed tunneling spectra. Here, we show that lower (upper) CMS electrodes possess a half-metal gap of 0.40 eV (0.32 eV) with the Fermi level (EF) near the middle of the half-metal gap for both lower and upper CMS electrodes. Furthermore, we found strong evidence for the existence of interface states in the interfacial region of CMS electrodes facing a MgO barrier, as well as evidence of residual states in the bulk region of upper CMS electrodes, in both cases for minority spins around EF, and we show that interface states play a crit...