水热合成单晶La_(1-x)Ca_xMnO_3系列纳米线

Synthesis of a Series of Single-crystalline La_(1-x)Ca_xMnO_3 Nanowires by Hydrothermal Method

采用水热法,成功地合成了一系列单晶La1-xCaxMnO3(x=0．3、0．5、0．75)纳米线．X射线衍射(XRD)的结果表明所制备的样品是纯的La1-xCaxMnO3正交相(x=0．3、0．5、0．75)纳米线．透射电子显微镜(TEM)的照片清晰地显示所制备的样品是由大量直径均匀(约90nm)、长度从几微米至几十微米的La1-xCaxMnO3的单晶纳米线构成．La0．5Ca0．5MnO3纳米线清晰的高分辨电子显微镜(HRTEM)的图片表明纳米线的表面是光滑的,没有任何缺陷且La0．5Ca0．5MnO3纳米线沿<100>方向生长．La0．5Ca0．5MnO3纳米线磁测量的结果表明相对于块材来说纳米线的Tc有明显地提高,这是由于晶胞收缩和形状各向异性所致．

A series of single-crystalline La1-xCaxMnO3 nanowires were successfully prepared by a hydrothermal method. X-ray diffraction （XRD） results demonstrate that the La1-xCaxMnO3 nanowires have orthorhombic perovskite structure without any impurity phases. Transmission electron microscope （TEM） images clearly show that the as-synthesized samples are made up of large quantities of single crystal nanowires with lengths ranging from several to several tens of micrometers and uniform diameter （about 90nm）. The high-resolution transmission electron microscope（HRTEM） investigations of La0.5Ca0.5MnO3 nanowires indicate that the nanowires have very clean surfaces without any defects and grow along 〈 100 〉 direction. The result of magnetic measurement indicates that the La0.5Ca0.5MnO3 nanowires have an enhanced Tc due to the shrinkage of unit cell volume and shape anisotropy.