1994 Fiscal Year Final Research Report Summary
High Resolution Inverse Photoemission System with Polarization Analysis
| Project/Area Number |
04559008
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
広領域
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| Research Institution | Osaka University |
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Principal Investigator |
SUGA Shigemasa Osaka University, Faculty of Engineering Science, Professor, 基礎工学部, 教授 (40107438)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIDA Norihide Shimadzu Co.Ltd. Member, 東京支社, 課長(研究者)
ZENITANI Fukuo Shimadzu Co.Ltd. Manager, 東京支社, 専門課長(研究者)
IMADA Shin Osaka University, Faculty of Engineering Science, Research Assistant, 基礎工学部, 助手 (90240837)
DAIMON Hiroshi Osaka University, Faculty of Engineering Science, Associate Professor, 基礎工学部, 助教授 (20126121)
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| Project Period (FY) |
1992 – 1994
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| Keywords | IPES / VUV / Spin polarization / NEA Cathode / High Resolution / Unoccupied State |
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| Research Abstract |
The inverse photomission(IPES) spectroscopy with capabilities of polarization analysis and very high resolution is strongly required to probe the electronic states very near the Fermi level. A system which satisfies such requirements is developed and partly tested. The high energy resolution of the band pass detector is realized by use of the difference spectrum between two IPES spectra measured with a SrF_2 low pass filter set at two different temperatures. The energy shift of the Urbach tail due to the excitonic absorption edge enables one to measure the IPES spectrum with different band pass characteristics. So the difference spectrum realizes a resolution better than 0.25 eV.
The energy band width of the excitation electron beam can be reduced by use of the negative electron affinity(NEA) GaAs cathode with use of Cs and O_2 deposition. For this purpose, not only an in-vacuum Ar bombard cleaning but also a preceding chemical cleaning is very important. In order to realize a good vacuum for NEA cathode, we installed NEG(non evaporating getter pump) and a high pumping speed ion pump. The transmittance of the electron lens is improved up to 50-80%. We finally got photoelectron current of more than 10 A with a life time of more than 10 hours.
In addition, 3 grids LEED(low energy electron diffraction) and Auger optics are installed. Pulse magnet system to magnetize ferromagnetic samples is also developed. This is used to measure the polarization dependence spectrum of ferromagntic materials.
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