NiLaxFe2-xO4 (x = 0.01, 0.03, 0.05, 0.07 and 0.09) nanoferrites were prepared using the sonochemical reaction method. The prepared nanoferrites were investigated using X-ray diffraction (XRD), ultra violet-diffuse reflectance spectroscopy (UV-DRS), Fourier transform infrared spectroscopy, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, electrochemical impedance spectroscopy and a vibrating sample magnetometer to explore their structural, optical, dielectric and magnetic properties. The analysis of the XRD pattern of these NiLaxFe2-xO4 nanoferrites confirmed the formation of a cubic spinel structure. The average crystallite sizes of the nanoparticles were 54, 49, 47, 43 and 40 nm for the composition x = 0.01, 0.03, 0.05, 0.07 and 0.09, respectively. An impedance analysis of the prepared nanoferrites was carried out to explore the dielectric behavior. Characterization studies indicated that the addition of La to NiLaxFe2-xO4 nanoparticles improved the dielectric properties of the prepared nanoferrites. The hysteresis loops promoted the ferro magnetic behavior present in the prepared NiLaxFe2-xO4 nanoferrites. A decrease in saturation magnetization and an increase in coercivity were observed with an increase in the La content in the prepared nanoferrites. (C) 2018 Elsevier B.V. All rights reserved.