Li Congli, Che Ping, Sun Changyan, Li Wenjun
J Nanosci Nanotechnol. 2016 Mar;16(3):2719-24. doi: 10.1166/jnn.2016.10922.
Zn(1-x)Co(x)O (x = 0-0.07) single-crystalline nanorods were prepared by a modified microemulsion route. The crystalline structure, morphology, optical, and hysteresis loop at low and room temperature of as-prepared materials were characterized by XRD, TEM, PL spectra, and magnetic measurement respectively. The nanorods are 80-250 nm in diameter and about 3 μm in length. X-ray diffraction data, TEM images confirm that the materials synthesized in optimal conditions are ZnO:Co single crystalline solid solution without any impurities related to Co. The PL spectra show that the ferromagnetic samples exhibit strong Zn interstitials and oxygen vacancy emission indicating defects may stabilize ferromagnetic order in the obtained diluted magnetic semiconductors. Magnetic measurements show that the Zn(1-x)Co(x)O nanorods exist obvious ferromagnetic characteristics with T(c) above 300 K. M(s) and coercivities first increase and then decrease with dopant concentration increasing, reaching the highest for 3% doping level. The structural and magnetic properties of these samples support the hypothesis that the FM of DMS nanorods is due to a defect mediated mechanism instead of cobalt nanoclusters and carrier mediated.
通过改进的微乳液法制备了Zn(1-x)Co(x)O（x = 0 - 0.07）单晶纳米棒。分别采用XRD、TEM、PL光谱和磁性测量对所制备材料在低温和室温下的晶体结构、形貌、光学性质和磁滞回线进行了表征。纳米棒直径为80 - 250 nm，长度约为3 μm。X射线衍射数据、TEM图像证实，在最佳条件下合成的材料是不含任何与Co相关杂质的ZnO:Co单晶固溶体。PL光谱表明，铁磁样品表现出强烈的锌间隙和氧空位发射，表明缺陷可能使所获得的稀磁半导体中的铁磁序稳定。磁性测量表明，Zn(1-x)Co(x)O纳米棒存在明显的铁磁特性，居里温度高于300 K。随着掺杂浓度的增加，饱和磁化强度M(s)和矫顽力先增大后减小，在3%掺杂水平时达到最高。这些样品的结构和磁性性质支持了以下假设：稀磁半导体纳米棒的铁磁性是由缺陷介导机制而非钴纳米团簇和载流子介导的。
