本文利用高温油相法制备出尺寸、形状均一的MnO纳米颗粒,X射线衍射图(XRD)和透射电子显微镜(TEM)照片清晰表明MnO纳米颗粒为单一的面心立方岩盐晶体结构,尺寸为15 nm,粒径分布很窄.通过零场冷却(ZFC)和带场冷却(FC)的磁滞回线发现MnO纳米颗粒具有明显的交换偏置效应,而且磁滞回线同时表现出横向和纵向偏移.横向偏移说明纳米颗粒中两相复合的存在,纵向偏移说明了存在自旋玻璃相或者超顺磁相.进而通过不同频率下随温度变化的交流磁化率的测定,根据Mydosh的经验数值确认MnO纳米颗粒表面层为自旋玻璃相,并得到MnO纳米颗粒表面自旋玻璃相的转变温度为TSG=32 K.
CoPt3/Co multilayered nanowire（NW） arrays are synthesized by pulsed electrodeposition into nanoporous anodic aluminum oxide（AAO） templates. The electrochemistry deposition parameters are determined by cyclic voltammetry to realize the well control of the ratio of Co to Pt and the length of every segment. The x-ray diffraction（XRD） patterns show that both Co and CoPt3 NWs exhibit face-centered cubic（ fcc） structures. In the UV-visible absorption spectra,CoPt3/Co NW arrays show a red-shift with respect to pure CoPt3 NWs. Compared with the pure Co nanowire arrays, the CoPt3/Co multilayered nanowire arrays show a weak shape anisotropy and well-modulated magnetic properties. CoPt3/Co multilayered nanowires are highly encouraging that new families of bimetallic nanosystems may be developed to meet the needs of nanomaterials in emerging multifunctional nanotechnologies.
