Departments of Materials Science and of Basic Science, Kyushu Institute of Technology, 1-1 Sensui, Tobata, Kitakyushu 804-8550, Japan.
ACS Appl Mater Interfaces. 2009 Sep;1(9):1893-8. doi: 10.1021/am9003057.
Epitaxial indium-tin oxide (ITO) thin films were fabricated on a yttria-stabilized zirconia (YSZ) substrate by pulsed-laser deposition using magnetite (Fe(3)O(4)) nanoparticle dispersed ITO powders as a target. Magnetoresistance of the film at a field of 1 T was 39% at 45 K, and it stayed at 3% above 225 K. The film demonstrated cooling hysteresis in the temperature dependence of direct-current magnetization. Transmission electron microscopy revealed that phase-separated Fe(3)O(4) nanocrystals with widths of approximately 40-150 nm and heights of approximately 10-25 nm precipitated and grew epitaxially on the substrate in the film. Both the Fe(3)O(4)(111) and ITO(001) planes were parallel to the YSZ(001) plane. The Fe(3)O(4)(11-2) and -(1-10) planes were parallel to the ITO(100) and -(010) planes, respectively, and the planes connected smoothly at the grain boundary. The contour map of the electron density for the Fe(3)O(4)(111) plane by the first-principles electronic structure computation was similar to that for the ITO(001) plane. The [111]-oriented Fe(3)O(4) nanocrystals played the role of spin aligner for charge carriers of the epitaxial ITO film.
通过使用磁铁矿(Fe3O4)纳米颗粒分散的 ITO 粉末作为靶材,通过脉冲激光沉积在氧化钇稳定的氧化锆(YSZ)衬底上制备了外延铟锡氧化物(ITO)薄膜。在 1 T 的磁场下,该薄膜在 45 K 时的磁阻为 39%,在 225 K 以上时保持在 3%以上。该薄膜在直流磁化的温度依赖性方面表现出冷却滞后。透射电子显微镜显示,在薄膜中,宽度约为 40-150nm、高度约为 10-25nm 的相分离 Fe3O4 纳米晶体在衬底上外延析出和生长。Fe3O4(111)和 ITO(001)平面均与 YSZ(001)平面平行。Fe3O4(11-2)和-(1-10)平面分别与 ITO(100)和-(010)平面平行,并且在晶界处平滑连接。通过第一性原理电子结构计算得到的 Fe3O4(111)平面的电子密度等高线图与 ITO(001)平面的相似。[111]取向的 Fe3O4 纳米晶体在外延 ITO 薄膜的载流子中起自旋对齐器的作用。