The structural, magnetic and conducting properties of Co implanted ZnO crystalline films

S. Güner, O. Gürbüz, N. Akdoğan, R. Khaibullin, S. Çalışkan
Fatih University, TR

Keywords: magnetic semiconductors, spintronics, XRD, ferromagnetism, electric conductivity

Summary:

We deposited two different ZnO films by magnetron sputtering on Si (100) substrates with 400 nm thick. The 8 samples of each film were implanted by 40 keV Co+ ions at different fluencies varying from 0.25x1017 ions/cm2 to 2.0 x1017 ions/cm2. The crystal structure was analyzed by XRD. The films ZnO-1 and ZnO-2 have single reflection peaks of (100) and (002) respectively before the implantation. The Co+ implantation decreased crystalline quality and caused the formation of Co3O4 crystallites at remarkable magnitudes especially in the ZnO-1. The Scherrer method showed that the average crystallite size drop from 59 nm to 25 nm for ZnO-1 samples, but no remarkable change for the ZnO-2 samples after implantation. The magnetic properties were investigated by VSM. The M-H curves were recorded at room temperature and 10 K. The temperature dependence of M were checked by FC and zero FC (ZFC) M-T measurements in a range of 10-400 K. The films exhibit ferromagnetic behavior at room temperature and have Tc greater than 400 K. Magnetization increased with the increasing Co fluence. However, the antiferromagnetic Co3O4 decreased the magnetization. The electric conductivity of films was measured by FPP method. The conductivity mainly depends on crystalline quality. The secondary contribution is due to increasing concentration of Co ions. We discussed the structural, magnetic, and conducting properties of films due to possible applications for spintronic devices.