【摘要】 利用溶胶-凝胶法制备了不同组分的Zn0.95-xCo0.05LixO纳米颗粒,并通过透射电子显微镜、X射线衍射、紫外-可见吸收光谱和振动样品磁强计对其结构和磁性进行了系统的研究。结果表明,当Li掺杂比例在7%以下时,Zn0.95-xCo0.05LixO纳米颗粒仍具有很好的ZnO六角纤锌矿结构,但随着Li掺杂量的增加,晶格常数a和c值略有减小;Zn0.95-xCo0.05LixO的室温铁磁性随x的增大而显著增强。当Li掺杂量达到9%时,在Zn0.95-xCo0.05LixO纳米颗粒的XRD谱中检测出第二相的LiCoO2団簇,样品的铁磁磁化强度明显下降。表征结果显示Li掺入Zn0.95Co0.05O的反应过程可以分为3个阶段。前两个阶段分别在材料中引入了Li′Zn深能级缺陷和Li+填隙离子,第三个阶段则产生了LiCoO2第二相结构。样品铁磁性的变化与Li掺杂引入的这些缺陷和第二相有关,可由束缚磁极化子(BMP)模型解释。更多还原

【Abstract】 Zn0.95-xCo0.05LixO(x=0~0.09) nanocrystals were synthesized by sol-gel method.Detailed characterization by XRD,UV-Vis absorption spectrum,and vibration sample magnetometer(VSM) indicated that Li-Co co-doping did not change the Wurtzite structure of ZnO when x≤7%.With the increase of Li-dopant,the lattice constants a and c decreased owing to the substitution of Zn2+ by Li+ ions,the ferromagnetism increased gradually.However,the ferromagnetism droped sharply when Li-dopant increased to 9%.At the same time,second-phase clusters of LiCoO2 were detected in the XRD pattern and the lattice constants almost stopped decreasing.Experimental results suggested that the reaction of Li incorporation could be divided into 3 stages.Li′Zn deep-level defects and Li+i interstitials were induced into the material at the former two stages respectively,while the second-phase LiCoO2 formed at the third stage.These defects and second-phase structures induced by Li-doping played important roles in enhancing the ferromagnetism of the samples,which could be explained by the bound magneton polaron(BMP) model.更多还原