Structural characterization on composite materials of magnetic ultra-fine particles using Conversion Electron Mossbauer Spectroscopy with applied magnetic field

1)利用1x10^&lt；17&gt；57&gt；Fe离子注入Al_2O_3颗粒膜，完成了“外加磁场转换电子穆斯堡尔谱测量系统”的性能测试。这些结果将在第41届物理科学和工业放射性同位素年会和科学讲座(2004年7月6日)上公布。2)用外加磁场的电子探针测量了注入Fe的Al_2O_3(蓝宝石)颗粒膜中α-Fe超顺磁性粒子的尺寸分布，以寻求最佳的Fe离子注入剂量和适度退火剂量条件。结果已在2003年10月10日在横滨举行的IUMRS-ICAM2003会议上公布。3)为了探索溅射Fe-Al-O颗粒膜和Fe注入Al_2O_3颗粒膜TMR效应差异的根源，用CEMS研究了溅射Fe-Al-O颗粒膜中α-Fe粒子的铁离子状态和尺寸分布。这一结果已提交给在德国塞海姆举行的第二届Seeheim磁性会议。它已经被接受，目前正在审查过程中(参考文献4)。它是由Hayashi等人发现的。通过在Al_2O_3晶体中顺序注入Fe和Co离子，可以形成超顺磁性纳米颗粒。2)。还观察到Fe-Co注入Al_2O_3颗粒膜的磁流变率(12%)大于Fe-Co注入颗粒膜的MR比(8%)。然后，对这些样品进行了外加磁场的CEMS测量。

The research results of this project are summarized as follows:1) The performances of "Measurement system for Conversion Electron Mossbauer Spectroscopy(CEMS) with applied magnetic field" have been done using 1x10^<17> ^<57>Fe-implanted Al_2O_3 granular film. These results will be presented in 41st annual meetings on radioisotopes in the physical sciences and industries as well as scientific lectures (7/6/2004).2) The size distribution of α-Fe superparamagnetic particles in Fe-implanted Al_2O_3 (sapphire) granular film have been measured using CEMS with applied magnetic field, in order to search for the most suitable conditions on the doses of Fe ion implantation and moderate annealing. The results have been presented in IUMRS-ICAM2003 held at Yokohama, 10/10/2003 (ref. 3).3) In order to search for the origin of the difference between TMR effects for sputtered Fe-Al-O and Fe-implanted Al_2O_3 granular films, the iron ionic states and the size distributions for a-Fe particles in sputtered Fe-Al-O granular TMR films have investigated using CEMS without and with applied magnetic fields. This result was submitted to 2nd Seeheim Conference on Magnetism held at Seeheim, Germany. It has been accepted and the contribution is now in review process (ref.4).4) It was found by Hayashi et al. that the superparamagnetic nano-sized particles can be formed by sequential implantation of Fe and Co ions to Al_2O_3 crystal (ref. 2). Also it was observed that the MR ratio (12%) for Fe-Co-implanted Al_2O_3 granular film is larger than that (8%) for Fe-implanted one. Then, CEMS measurements with applied magnetic field for these samples are now performed.