Fabrication of Fully Epitaxial Magnetic Tunnel Junctions Using Full-Heusler Alloy Co2Cr0.6Fe0.4Al Thin Film and MgO Tunnel Barrier
Fabrication of Fully Epitaxial Magnetic Tunnel Junctions Using Full-Heusler Alloy Co2Cr0.6Fe0.4Al Thin Film and MgO Tunnel Barrier
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DOI：
10.1143/jjap.44.l521
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发表时间：
2005-04
影响因子：
1.5
通讯作者：
T. Marukame;T. Kasahara;K. Matsuda;T. Uemura;Masafumi Yamamoto
中科院分区：
文献类型：
--
作者：
T. Marukame;T. Kasahara;K. Matsuda;T. Uemura;Masafumi Yamamoto
采用Co基全Heusler合金Co2Cr0.6Fe0.4Al（CCFA）薄膜和MgO隧道势垒制备了全外延磁性隧道结（MTJ）。所制造的MTJ具有以下层结构：MgO缓冲层/CCFA下电极/MgO隧道阻挡层/CoFe上电极，生长在MgO单晶衬底上。所有的层都是通过磁控溅射和电子束蒸发的组合使用，在一个可调的真空室中连续沉积的。在制备过程中原位观察到的每一层的RHEED图案清楚地表明，所有层都以（001）基面外延生长。微制造的外延CCFA/MgO/CoFe MTJ表现出相对较高的隧道磁阻比，对于使用全Heusler合金的MTJ，在室温下为42%，在55 K下为74%。这些结果证实了使用Co基全Heusler合金作为关键器件结构的外延MTJ的前景，该关键器件结构利用了该材料系统的潜在高自旋极化。
Fully epitaxial magnetic tunnel junctions (MTJs) were fabricated using a Co-based full-Heusler alloy Co2Cr0.6Fe0.4Al (CCFA) thin film and a MgO tunnel barrier. The fabricated MTJs had the following layer structure: MgO buffer layer/CCFA lower electrode/MgO tunnel barrier/CoFe upper electrode, grown on a MgO single-crystal substrate. All layers were successively deposited in an ultrahigh vacuum chamber through the combined use of magnetron sputtering and electron beam evaporation. RHEED patterns observed in situ for each layer during preparation clearly indicated that all layers grew epitaxially with the (001) basal plane. The microfabricated epitaxial CCFA/MgO/CoFe MTJs demonstrated relatively high tunnel magnetoresistance ratios, for MTJs using a full-Heusler alloy, of 42% at room temperature and 74% at 55 K. These results confirm the promise of an epitaxial MTJ using a Co-based full-Heusler alloy as a key device structure utilizing the potentially high spin polarization of this material system.