MnF_2纳米晶的合成及表征

SYNTHESIS AND CHARACTERIZATION OF MnF_2 NANOCRYSTAL

室温下成功地合成了MnF2纳米晶.它的X-射线衍射图(XRD)中所有的衍射峰均指标化为金红石结构的MnF2,晶胞参数为a=0.485 7 nm,c=0.330 9 nm.从扫描电镜图中可以看到,所制备MnF2纳米晶的形貌是球形颗粒,尺寸大约在20 nm左右.它的吸收光谱显示出Mn2+的d-d跃迁的特征吸收.磁性质表征显示在70.0 K处MnF2纳米晶从反铁磁性转变为顺磁性,在2 K温度下,表现出线性磁行为.

MnF2 nanocrystals were prepared at room temperature.X-ray diffraction（XRD） pattern of the powder form was indexed to the rutile-type structure with lattice constant a=0.4857 nm and c=0.3309 nm.MnF2 nanocrystals were spherical particles with a size of 20 nm by scanning electron microscopy analysis.Its optical absorption spectrum exhibited absorption features of Mn2＋ d-d transitions.Magnetic characterization indicated that the nanocrystals had anti-ferromagnetic-paramagnetic phase transition at 70.0 K,and showed linear magnetization at 2 K.