Synthesis, structural investigation, dielectric and magnetic properties of Zn2+-doped cobalt ferrite by the sol–gel technique

Abstract

Zinc substituted cobalt ferrite nanoparticles with elemental composition Co[Formula: see text]Zn x Fe 2 O 4 ([Formula: see text], 0.2, 0.4, 0.6) were prepared by the sol-gel auto-combustion technique using Co, Fe, Zn nitrate as a precursor where nitrates to citrate was 1:3. The as prepared powder of cobalt zinc ferrite was sintered at 900 ∘ C for 3[Formula: see text]h. Structural, morphological, dielectric and magnetic properties were studied by x-ray diffractometer (XRD), scanning electron microscope (SEM), high precision impedance analyzer and vibrating sample magnetometer (VSM), respectively. The peaks obtained from the XRD confirmed samples having crystallite ([Formula: see text]32–36[Formula: see text]nm) single phase inverse spinel structure without any traceable impurity. Lattice parameters were calculated from XRD and it increases with Zn content. SEM revealed irregularly shaped grains ([Formula: see text]–0.7[Formula: see text][Formula: see text]m) morphology with heterogeneous distribution. The dielectric constant ([Formula: see text]) and dielectric loss ([Formula: see text]), have been measured as a function of frequency at room temperature. The dependence of [Formula: see text] and [Formula: see text] with frequency showed the normal dielectric behavior in accordance with the Maxwell-Wagner type of interfacial polarization and electron hopping change between Co[Formula: see text] and Co[Formula: see text] as well as between Fe[Formula: see text] and Fe[Formula: see text] ions at octahedral sites.