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

本研究项目的目的是构建高性能布里渊光谱仪，并利用该光谱仪研究半导体衬底上生长的超薄膜和多层薄膜。这三年（1987-1990）所取得的成果总结如下：我们开发了一种高性能串联五通法布里-珀罗干涉仪，可以测量不透明金属薄膜中声波和自旋波的布里因光谱。在光学、多通道系统方法、精密控制法布里-珀罗反射镜的压电陶瓷元件和电路等方面进行了新的尝试。该干涉仪稳定性高，即使是光谱测量的初学者也易于操作。进一步引入减振台，消除外部振动。因此，对金属薄膜进行详细的布里渊研究成为可能。用布里渊法研究了在Si衬底上沉积Co-…More Au-Co和Co- nb -Co三层薄膜。研究了Co层之间通过非磁性金属层的交换相互作用，由于电子密度的差异，Au层比nb层的交换相互作用更大。本文还测量了用于垂直磁记录介质的多层Tb-(Fe,Co)薄膜的自旋波谱。广泛的不对称自旋波谱已被观测到。它们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钴铂合金薄膜。研究了自旋波谱与合金成分的关系。这些合金薄膜中的自旋波谱明显展宽，这是由合金薄膜的晶粒结构引起的。为了阐明Pt在分离磁性共晶中的作用，测量了Co双层与Pt中间层之间的交换作用。在此基础上，研究了高密度磁记录介质的合金成分和晶粒结构的优化条件。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