Study of Surface Spin Wave by use of Variable Temperature Conversion Electron Spectrometer for Mossbauer Spectroscopy

本研究的目的是用变温转换电子穆斯堡尔谱测量样品&lt；Fe_(1-x)O&gt；(Wusite)、&lt；Fe_3O_4&gt；(磁铁矿)和&lt；FeF_2&gt；(氟化铁)的表面磁化强度和块体磁化强度随温度变化的差异。富集型&lt；(57)Fe&gt；氧化物薄膜是在&lt；O_2&gt；分压为&lt；10^(-16.5)&gt；大气压下制备的。在800℃时，用He+10%&lt；CH4&gt；转换电子穆斯堡尔谱正比计数器观察到该薄膜由&lt；Fe_3O_4&gt；，&lt；Fe_(1-x)O&gt；和-Fe组成。之后，用上述电子能谱仪测量了薄膜的穆斯堡尔谱。对于6.6keV，7.15keV和7.3keV，分别在5，6和2个不同的温度下获得了光谱。虽然由于穆斯堡尔源强度不大(30 MCi)，统计结果不太令人满意，但得到如下结果：1)该氧化铁膜由表层到深层依次由&lt；Fe_3O_4&gt；，&lt；Fe_(1-x)O&gt；和-Fe组成。2)~lt；Fe_(1-x)O&gt；的转变温度在176~206K之间，在低于156K的温度下，~lt；Fe_(1-x)O&gt；的超精细场与&lt；Fe_3O_4&gt；的超精细场基本一致。3)在78K下测得的7.3keV谱中，有一组分的&lt；Fe_3O_4&gt；为了证实第三个结果，将用比现在更强的穆斯堡尔源进行Fe_3O_4&GT；富集膜。

It was an aim of this study to measure the difference between a temperature dependence of magnetization at surface and that in bulk of the samples; <Fe_(1-x)O> (Wustite), <Fe_3O_4> (Magnetite) and <FeF_2> (Iron fluoride), by use of temperature variable conversion electron Mossbauer spectroscopy. The enriched <^(57)Fe> oxide thin film was made under the <O_2> partial pressure of <10^(-16.5)> atm. and at the temperature of 800 C. This film was observed to be composed of <Fe_3O_4> , <Fe_(1-x)O> and -Fe by use of a He + 10% <CH_4> proportional counter for Conversion Electron Mossbauer Spectroscopy. After then, Mossbauer spectra for the film have been measured with the electron spectrometer mentioned above. For 6.6 keV, 7.15keV and 7.3 keV, the spectra have been obtained at 5, 6 and 2 different temperatures, respectively. Although the statistics of these were not so satisfactory because the Mossbauer source used was not strong(30 mCi), the following results were obtained.1) This iron oxide film is composed of <Fe_3O_4> , <Fe_(1-x)O> and -Fe from surface to deeper region sequentially. 2) The transition temperature of <Fe_(1-x)O> is between 176 K and 206 K and the hyperfine field of <Fe_(1-x)O> nearly coincides with that of <Fe_3O_4> at lower temperature than 156 K. 3) It is observed that in 7.3 keV spectrum,measured at 78 K, there is a component of <Fe_3O_4> with the hyperfine field larger than those in the other energies at the same temperature.Nextly, the same measurements for <Fe_3O_4> enriched film will be done with the Mossbauer source stronger than the present in order to confirm the third result.