Growth mechanism and Electron Spin Resonance Studies of Zn1-xNixO/NiO Two-Phase Nanocomposite

Abstract

Two-phase nanocomposites comprised of Zn 1-x Ni x O/NiO (0.05 ≤ x ≤ 0.3) were grown by using sol-gel process with hydrated metal acetates as precursors. Thermal decomposition of the co-precipitated oxalate α-ZnNi(C 2 O 4 ) yields wurtzite h.c.p. Zn 1-x Ni x O and f.c.c. NiO together. The X-band electron spin resonance spectra provide the signatures of anisotropic spin interactions with long-range magnetic ordering at 300 K. The temperature variation (120 K ≤ T ≤ 300 K) of the resonance field H R (T) and line-width ΔH PP (T) depicts a clear anomaly across 140 K associated with the blocking/freezing effects and the contribution of additional surface anisotropy (K eff ) present in the system. Both H R (T) and ΔH PP (T) follows the power-law variation δH R = (ΔH PP ) n with n ≃ 2.13, as expected for partially oriented nanocrystallites.