Research on the quaternary diluted magnetic semiconductor films exhibiting the large Faraday-rotation and their magneto-optical application to the high frequency magneto-optical sensors

II-VI半导体CdMnTe被称为稀释磁性半导体（DMS），它具有顺磁性，并在室温下表现出相当大的法拉第效应。在DMS晶格中，Mn的存在导致Mn^<2+>离子的三维电子与带电子之间的局域磁矩发生自旋-自旋交换相互作用。这种相互作用在室温下产生了法拉第效应。由于这些特性，从应用角度来看，CdMnTe已成为磁光器件的主要关注点。为了提高DM5薄膜的磁光性能，我们采用分子束外延（MBE）技术研究了在透明SiO_2石英玻璃衬底上沉积的四元DMS CdMnCoTe薄膜的法拉第旋转，结果表明法拉第效应得到了增强。本研究从磁光在可见光区域的应用角度研究了CdMnCoTe薄膜的磁光特性。将CdMnCoTe薄膜中的法拉第效应与CdMnTe薄膜和铁磁性石榴石薄膜中的法拉第效应进行了比较。本研究进行了以下工作：(1)利用激光二极管作为光源，在635 nm处直接观察了QG衬底上顺磁性MnCo: DMS厚膜中的法拉第效应。(2)明确了MnCo: DMS薄膜对磁场的线性特性。在635 nm处，Cd_<0.43>Mn_<0.54>Co_<0.03>Te薄膜的光吸收与Cd_<0.40>Mn_<0.60>Te薄膜相同，因此CdMnCoTe薄膜的光能值比CdMnTe薄膜提高了4倍。通过在更薄的衬底上制备大于5μm的厚膜，提高光学系统的透过率，可以进一步提高法拉第旋转信号的信噪比。我们将继续努力，利用我们开发的具有较大法拉第旋转的四元DMS薄膜开发高频磁光传感器。少

The II-VI semiconductor CdMnTe is known as a diluted magnetic semiconductor (DMS) that shows paramagnetic characteristics and exhibits a considerable Faraday effect at room temperature. In the DMS lattice, the presence of Mn leads to a spin-spin exchange interaction between the localized magnetic moments due to 3d electrons of the Mn^<2+> ion and the band electrons. This interaction gives rise to the Faraday effect at room temperature. Because of such characteristics, the CdMnTe has become of major interest from its application viewpoint to magneto-optical devices. In order to improve the magneto-optical property in DM5 films, we have studied the Faraday rotation in the four-element DMS CdMnCoTe films deposited on transparent SiO_2 quartz glass substrates by using molecular beam epitaxy (MBE), and showed that the Faraday effect is enhanced in those films.In this research, the magneto-optical properties of CdMnCoTe films are studied from the viewpoint of magneto-optical application in t … More he visible region. The Faraday effect in the CdMnCoTe films is compared with that of the CdMnTe film and a ferrimagnetic garnet filmThe following were performed in this research : (1)The Faraday effect in the paramagnetic MnCo : DMS thick film on QG substrate was directly observed at 635 nm using a laser diode as the light source. (2)The linear characteristics to the magnetic fields were clarified in the MnCo : DMS film.Optical absorption for Cd_<0.43>Mn_<0.54>Co_<0.03>Te film at 635 nm is identical for Cd_<0.40>Mn_<0.60>Te film, and, therefore, the figure of merit has been improved in the CdMnCoTe film by four times to the CdMnTe film. It is expected that the signal to noise ratio of the Faraday-rotation signal can be further improved by preparing thick films more than 5μm on thinner substrates and raising transmissivity of the optical system.We are going to continue with every effort in order to develop the high-frequency magneto-optical sensors using quaternary DMS films, which exhibit the large Faraday-rotation, developed by us. Less