Effect of the Zn content in the magnetic properties of Co_(1-x)Zn_xFe_2O_4 mixed ferrites

摘要

In this work, the effect of Zn content in the magnetic properties of Co_(1-x)Zn_xFe_2O_4 (0.0 ≤ x ≤ 1.0) nanoparticles synthesized by combustion reaction method was investigated by applying magnetic fields up to 20 kOe at room temperature. All the samples were found to have a cubic spinel structure and the lattice parameter increases linearly with increasing Zn-content. The hysteresis loops yield a saturation magnetization (M_s), coercive field (H_c), and remanent magnetization (M_r) that varies significantly with Zn-content. For instance, M_s, H_c, and Mr are 70 emu/g, 600 Oe, and 20 emu/g and 8 emu/g, 0.0 Oe, and 0.0 emu/g for x = 0.0 and x=1.0, respectively. The Curie temperature determined by means of the inverse susceptibility versus temperature decreases with increasing x, being ～787 K and ～634 K for x = 0.0 and 1.0, respectively. The magnetic cubic anisotropy constant for different Zn-contents, determined by a "law of approach" to saturation, was found to be smaller than those values for pure cobalt ferrites nanoparticles and strongly dependent on x, being 3.87 × 10~6 erg/cm~3 and 0.22 × 10~6 erg/cm~3 for x = 0.0 and 1.0, respectively, at room temperature. A discussion on the implications of the Zn-content in the determination of the anisotropy constant in these materials will also be presented.