Direct observation of half-metallic energy gap in Co2MnSi by tunneling conductance spectroscopy
Direct observation of half-metallic energy gap in Co2MnSi by tunneling conductance spectroscopy
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DOI：
10.1063/1.2335583
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发表时间：
2006-08
影响因子：
4
通讯作者：
Y. Sakuraba;T. Miyakoshi;M. Oogane;Y. Ando;A. Sakuma;T. Miyazaki;H. Kubota
中科院分区：
文献类型：
--
作者：
Y. Sakuraba;T. Miyakoshi;M. Oogane;Y. Ando;A. Sakuma;T. Miyazaki;H. Kubota
用磁控溅射方法制备了Co2MnSi/Al-O/CoFe结构的磁性隧道结，并对其费米能级附近的能隙进行了研究。Al-O势垒的等离子体氧化时间影响Co2MnSi/Al-O界面的状态。优化后的样品(氧化时间为50s)在2K时的磁电阻率为159%，隧道自旋极化为0.89。隧道电导的偏置电压依赖关系(Di/dV−V)表明，Co2MnSi在350-400 meV处有明显的半金属能隙，费米能与导带底缘之间的能量间隔仅为10 meV。
Magnetic tunnel junctions with a Co2MnSi∕Al–O∕CoFe structure are prepared by magnetron sputtering and investigated with respect to the energy gap near the Fermi energy level. The plasma oxidation time for the Al–O barrier is found to affect the condition of the Co2MnSi∕Al–O interface. The optimized sample (50s oxidation time) exhibits a magnetoresistance ratio of 159% and tunneling spin polarization of 0.89 at 2K. The bias voltage dependence of tunneling conductance (dI∕dV−V) reveals a clear half-metallic energy gap at 350–400meV for Co2MnSi, with an energy separation of just 10meV between the Fermi energy and the bottom edge of conduction band.