Structure and Magnetic Properties of (Al, Co) Co-Doped ZnO Thin Films
In this study, Zn0.99Co0.01Al0.015O thin film has been prepared by sol-gel method. The structural and magnetic properties of the sample were investigated. X-ray diffraction spectroscopy analyses indicate that the Co and Al codoping can not disturb the structure of ZnO. No additional peaks are observed in the Zn0.99Co0.01AlxO and Al3+ and Co2+ substitute for Zn2+ without changing the wurtzite structure. The resistance measurements confirm that Al ions increase the free carriers concentration. Based on the above experiments we think the ferromagnetic behavior of the sample could not originate from Co nanoclusters. The presence of free carriers and localized d spins is a prerequisite for the appearance of ferromagnetism. As the result, the carriers generated by Al doping is considered a main factor to induce the ferromagnetic phenomenon.
Chunliang Zhang and Liangchi Zhang
P. Cao and Y. Bai, "Structure and Magnetic Properties of (Al, Co) Co-Doped ZnO Thin Films", Key Engineering Materials, Vols. 531-532, pp. 299-302, 2013