Detection of the valence band in buried Co2MnSi-MgO tunnel junctions by means of photoemission spectroscopy

被引:46
作者
Fecher, Gerhard H. [1 ]
Balke, Benjamin [1 ]
Gloskowskii, Andrei [1 ]
Ouardi, Siham [1 ]
Felser, Claudia [1 ]
Ishikawa, Takayuki [2 ]
Yamamoto, Masafumi [2 ]
Yamashita, Yoshiyuki [3 ]
Yoshikawa, Hideki [3 ]
Ueda, Shigenori [3 ]
Kobayashi, Keisuke [3 ]
机构
[1] Johannes Gutenberg Univ Mainz, Inst Anorgan Chem & Analyt Chem, D-55099 Mainz, Germany
[2] Hokkaido Univ, Div Elect Informat, Sapporo, Hokkaido 0600814, Japan
[3] Natl Inst Mat Sci, Mikazuki, Hyogo 6795148, Japan
关键词
D O I
10.1063/1.2931089
中图分类号
O59 [应用物理学];
学科分类号
摘要
This work reports on the detection of the valence band of buried Heusler compounds by means of hard x-ray photoemission spectroscopy. The measurements have been performed on the so-called "half" tunnel junctions that are thin films of Co2MnSi underneath MgO. Starting from the substrate, the structure of the samples is MgO(buffer)-Co2MnSi-MgO(t(MgO))-AlOx with a thickness tMgO of the upper MgO layer of 2 and 20 nm. The valence band x-ray photoemission spectra have been excited by hard x rays of about 6 keV energy. The valence band spectra have been used to estimate the mean free path of the electrons through the MgO layer to be 17 nm at kinetic energies of about 6 keV. In particular, it is shown that the buried Co2MnSi films exhibit the same valence density of states as in bulk samples. (c) 2008 American Institute of Physics.
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页数:3
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