Co掺杂ZnO薄膜的结构和磁学性能

研究了用单束脉冲激光沉积法制备的Co掺杂ZnO薄膜的结构和磁学性能。XRD表征结果表明制备的薄膜是具有沿c轴择优取向的纤锌矿点阵结构。然而,进一步的高分辨电子显微镜结果显示整个样品上的晶体取向并不完全相同。很难说明形成了单晶。结果分析表明Co占据了部分Zn的格点,并对电子结构产生了影响。室温下观察到了磁滞回线,显示掺杂Co可以实现ZnO的磁性翻转,但磁性比较小。该薄膜与我们以前用双束脉冲激光沉积法制备的Co掺杂ZnO薄膜具有相似的性能,提示我们其内部的机制可能相似。

Structural and Magnetic Properties of Co-doped ZnO Thin Films

Co-doped ZnO films were fabricated using a pulsed laser deposition method on c-sapphire substrates. The structural and magnetic properties of the Co-doped ZnO films have been studied in this paper. The XRD characterization results show that they are wurtzite structures with the c-axes of the films aligning with those of the substrates. However the films do not grow along with the same orientation on the whole area of the specimens based on the HRTEM results. It is hard to conclude that the films were formed to be single crystals. The results reveal the occupation of Co ions at Zn sites in the host lattice. The studies of the electronic structures of the thin films show that the addition of Co ions into the Zn sites in the host ZnO affects the electronic band structure of the material. Magnetic hysteresis loops (M-H) were observed at room temperature, suggesting that the magnetism could be realized by Co-doping into ZnO. However, the improvement is limited. The work is following our previous reports on ZnO based diluted magnetic semiconductors, in which Co-doped ZnO thin films were synthesized using a dual-beam pulsed laser deposition method, suggesting their intrinsic mechanisms involved are probably similar.