STUDY OF SUPER-THIN FILMS DEPOSITED ON SEMICONDUCTOR-SUBSTRATES BY BRILLOUIN SPECTROSCOPY OF SURFACE WAVES

本研究项目的目标是构建一台高性能的布里渊光谱仪，并利用该光谱仪对半导体衬底上生长的超薄膜和多层膜进行研究。1.我们研制了一台高性能串联式五通法布里-珀罗涉仪，可以测量不透明金属薄膜中声波和自旋波的布里渊谱。在光学、多程系统方法、用于法布里-珀罗镜精细控制的压电陶瓷元件和电路等方面进行了新的尝试。所构建的干涉仪具有很高的稳定性，即使是光谱测量的初学者也很容易处理。为了消除外界的振动，进一步引入了减振台。因此，有可能对金属薄膜进行详细的布里渊研究。已经对Co-…进行了布里渊研究在硅衬底上沉积了更多的Au-Co和Co-Nb-Co三层膜。研究了Co层与非磁性金属层之间的交换作用，由于电子密度的不同，Au层的交换作用大于Nb层，并测量了用于垂直磁记录介质的Tb-(Fe，Co)多层膜的自旋波谱。观察到了广泛的不对称自旋波谱。这些都是由多层结构中的多模自旋波组成的。对多模自旋波谱进行了定量解释。采用溅射法制备了用于水平磁记录介质的Co-铂合金薄膜。研究了合金成分对自旋波谱的影响。合金薄膜中的自旋波谱明显展宽，这是由于合金薄膜的晶格结构所致。为了阐明铂对磁性钴颗粒的分离作用，测量了钴双层膜与铂中间层的交换作用。根据这些结果，研究了制备高密度磁记录介质的合金成分和晶粒结构的最佳工艺条件。较少

The objective of this research project is the construction of a high performance Brillouin spectrometer and studies of super-thin films and multi-layer films grown on semiconductor substrates by using this spectrometer. The obtained results in these three years (1987-1990) is summarized as follows:1. We have developed a high performance tandem 5-pass Fabry-Perot interferometer, which can measure the Brillouin spectra of acoustic and spin waves in opaque metallic films. New attempts are made on the optics, the method of multi-pass system, the piezo-ceramic elements for fine controlling of the Fabry-Perot mirrors, and the electrical circuits. The constructed interferometer show high stability and is easy to treat even for a beginner of the spectroscopic measurements. Further antivibration table are introduced to eliminate the vibration from outside. As a result, it has been possible to make detailed Brillouin study of the metallic thin films.2. Brillouin studies have been made on the Co- … More Au-Co and Co-Nb-Co triple-layered films deposited on Si substrates. The exchange interaction between the Co layers through the nonmagnetic-metal layer is investigated, which is larger in case of the Au layer than in the Nb-layer case due to the difference of the electron density.The spin wave spectra are also measured in multi-layered films of Tb-(Fe,Co), which is fabricated for the vertical magnetic recording media. Broad asymmetric spin-wave spectra have been observed. These are composed of the multi-mode spin waves in the multi-layered structure. Quantitative interpretation has been made on the multi-mode spin wave spectra.3. Co-Pt alloy films for the horizontal magnetic recording media are prepared by sputtering. The spin wave spectra are investigated as a function of the alloy composition. The spin wave spectra in these alloy films are remarkably broadened, which is caused by the crystal grain structure of the alloy films. To elucidate the role of Pt which separates the magnetic Co-grains, the exchange interaction of the Co double-layers with the Pt interlayer has been measured. From these results, optimum conditions are studied on the alloy composition and the grain structure for the high-density magnetic recording media. Less