Crystallographic, magnetic and electrical properties of Ni0.5Cu0.25Zn0.25LaxFe2−xO4 nanoparticles fabricated by sol–gel method

The Ni0.5Cu0.25Zn0.25LaxFe2−xO4 (x = 0.0, 0.25, 0.50, 0.75, 1.0) ferrite nanoparticles were fabricated by a sol–gel method. The crystallographic and magnetic properties of the powders were investigated by X-ray diffraction (XRD), transmission electron micrography (TEM), infrared spectroscopy (IR), vibrating sample magnetometer (VSM) and DC resistivity measurements. Phase identification of the samples was studied by the XRD patterns. XRD patterns shows the characteristics XRD peaks corresponding to the cubic spinel structure ferrites with the presence of secondary LaFeO3 phase. The lattice constant, porosity and specific surface area was increased whereas particle size, bulk density decreased with the increase in La3+ substitution. The TEM study reveals the fine particle nature of the ferrites with little agglomeration. The saturation magnetization (Ms) and coercivity (Hc) of the Ni–Cu–Zn samples were decreased with the La3+ substitution. DC resistivity indicates the semiconducting nature of the prepared samples. It has been found that the La3+ ions have a critical influence on the resultant structure, magnetic and resistivity properties of the Ni–Cu–Zn samples.

► La3+ substituted Ni–Cu–Zn ferrite.
► Crystallite size decreased with La3+ substitution.
► Magnetization and coercivity decreased with La3+ substitution.
► Resistivity increased with La3+ substitution.