80% tunneling magnetoresistance at room temperature for thin Al-O barrier magnetic tunnel junction with CoFeB as free and reference layers
80% tunneling magnetoresistance at room temperature for thin Al-O barrier magnetic tunnel junction with CoFeB as free and reference layers
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DOI：
10.1063/1.2696590
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发表时间：
2007-04
影响因子：
3.2
通讯作者：
Hongyuan Wei;Q. Qin;M. Ma;R. Sharif;Xuefeng Han
中科院分区：
文献类型：
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作者：
Hongyuan Wei;Q. Qin;M. Ma;R. Sharif;Xuefeng Han
采用超真空磁控溅射（ULVAC）方法制备了具有Ta（5）scinCu（10）scinTa（5）scinIr 21 Mn 79（10）scinCo 75 Fe 25（2）scinRu（0.75）scinCo 40 Fe 40 B20（3）scinAl（0.6）-O scinCo 40 Fe 40 B20（2.5）scinTa（3）scinRu（7）结构的磁性隧道结（MTJ）（单位为纳米）。采用标准的紫外光刻结合离子刻蚀技术，制备了外径为2μm、内径为1μm的微型环形磁性隧道结（RMTJ）。参考层和自由层都是Co 40 Fe 40 B20，并且使用非常薄的Al-O（0.6nm）阻挡层。在室温和4.2K下，观察到高达81%和107%的Tunnel磁阻（TMR）。这些RMTJ具有高TMR和约26 Oe的低磁导率，结合环形几何形状，大大减少了杂散磁场，是某些磁场传感器应用的理想选择。
Magnetic tunnel junctions (MTJs) with structures of Ta(5)∕Cu(10)∕Ta(5)∕Ir21Mn79(10)∕Co75Fe25(2)∕Ru(0.75)∕Co40Fe40B20(3)∕Al(0.6)–O∕Co40Fe40B20(2.5)∕Ta(3)∕Ru(7) (units in nanometers) were deposited via ultrahigh vacuum magnetron sputtering (ULVAC). Microscale ring-type magnetic tunnel junctions (RMTJs) with an outer radius of 2μm and an inner radius of 1μm were patterned using standard UV lithography combined with ion milling. Both reference and free layers were Co40Fe40B20 and a very thin Al–O (0.6nm) barrier layer was used. Tunneling magnetoresistances (TMRs) of up to 81% at room temperature and 107% at 4.2K were observed. These RMTJs with high TMR and low coercivity, of about 26Oe, combined with the ring-type geometry, which greatly reduces stray magnetic field, are ideal for certain magnetic field sensor applications.