Magnetic properties of ZnO:Co layers obtained by pulsed laser deposition method

We have studied magnetic properties of zinc oxide (ZnO) composite doped with Co ions. The samples were obtained by pulsed laser deposition (PLD) method. Electron magnetic resonance (EMR) measurements were carried out and temperature dependence of EMR spectra was obtained. Analysis of temperature dependence of the integral intensity of EMR spectra was carried out using Curie-Weiss law. Reciprocal of susceptibility of an antiferromagnetic (AFM) material shows a discontinuity at the Néel temperature and extrapolation of the linear portion to negative Curie temperature. The results of temperature dependence of EMR spectra for the ZnO:Co sample and linear extrapolation to the Curie-Weiss law indicated the AFM interaction between Co ions characterized by the Néel temperatures T_N = 50 K and T_N = 160 K for various samples. The obtained g-factor is similar to g-factors of nanocrystals presented in literature, and the results confirm that in the core of these nanocrystals Co was incorporated as Co²⁺, occupying Zn²⁺ sites in wurtzite structure of ZnO.