Structures and Magnetic Properties of Iron Nano-Crystals Embedded in Ceramic Glass Films

近年来，纳米颗粒磁性粒子嵌入绝缘基体中，由于出现了自旋相关磁阻效应，即“隧道型磁阻效应”，引起了人们的广泛关注。然而，关于磁性颗粒的纳米结构和形貌，如晶体结构、取向、大小、平均颗粒间距离和磁性颗粒的分布，与颗粒之间的磁相互作用及其磁性能之间的关系的研究很少。在本研究中，(1)在不同的衬底温度和蒸发条件下，通过电子束蒸发将Fe和Co纳米颗粒沉积在Al_2O_3绝缘薄膜上。并在电镜观察纳米颗粒膜结构和形貌的基础上，讨论了其磁性能。在本研究中，(2)制造了一种“转移室”，可以将蒸发室中形成的纳米颗粒膜直接转移到电子显微镜中，而不会使样品氧化或在空气中污染。

In recent years nano-granular magnetic particles embedded in insulating matrix has been attracting much interest, because of the appearance of spin-related magnetic resistance (MR) effect called "tunneling-type MR effect". However, little investigations have been made which relate nano-structures and morphologies of the magnetic particles, such as crystal structure, orientation, size, average inter-particle distance and distribution of magnetic particles, to magnetic interactions between the particles and their magnetic properties.In the present study, (1) Fe and Co nano-particles were deposited onto insulating Al_2O_3 films by electron-beam evaporation under various substrate temperatures and evaporation conditions. And their magnetic properties were discussed on the basis of structures and morphologies of the nanogranular films observed by electron microscopy. Also in this study, (2) a "transfer-chamber" was manufactured which transfers nano-granular films formed in an evaporation chamber directly into an electron microscope without specimen oxidation or contamination in air.