You C Y, Tian N, Lu Z X, Ge L L
Xi'an University of Technology, Xi'an 710048, P R. China.
J Nanosci Nanotechnol. 2012 Feb;12(2):1099-104. doi: 10.1166/jnn.2012.4264.
During ordering process of face centered tegragonal (fct) L1(0) phase of the FePt alloy, there exist three growth variants of axes (001) from original disordered fcc structured phase. When FePt film was directly deposited on the MgO (001) substrate, the variant perpendicular to the film plane grew, resulting in a low out-of-plane coercivity of 1.3 kOe. By using Cu underlayer, two variants lying in the film plane got same chance to grow, which caused an in-plane perpendicular alignment of the tetragonal axes of FePt L1(0) phases. The crystallographic relationship between Cu and FePt layers is Cu (100)<100>//fct FePt (100)<100>. A high in-plane coercivity of 4.6 kOe was obtained due to the high density of micro-defects (mcro-twins, anti-phase boundaries, etc.) in the film plane. This work demonstrated a way of selecting the growth variants of ordering process to adjust the magnetic properties of the ordered FePt thin films.
在FePt合金面心四方（fct）L1(0)相的有序化过程中，从原始无序的面心立方（fcc）结构相存在三种（001）轴的生长变体。当FePt薄膜直接沉积在MgO（001）衬底上时，垂直于薄膜平面的变体生长，导致面外矫顽力低至1.3 kOe。通过使用Cu底层，位于薄膜平面内的两个变体有相同的生长机会，这导致FePt L1(0)相的四方轴在面内垂直排列。Cu和FePt层之间的晶体学关系为Cu (100)<100>//fct FePt (100)<100>。由于薄膜平面内存在高密度的微缺陷（微孪晶、反相边界等），获得了4.6 kOe的高面内矫顽力。这项工作展示了一种通过选择有序化过程的生长变体来调节有序FePt薄膜磁性能的方法。
