Zn0.5Cr0.5LaxFe2-xO4 nanoferrites with varied compositions of x = 0.03, 0.06, 0.09, and 0.12 were synthesized using an effective sonochemical reactor. The powders resulting from this synthesis were characterized by X-ray diffraction (XRD) and scanning electron microscopy, energy dispersive X-ray spectroscopy, and their electrical and magnetic properties examined by electrochemical impedance spectroscopy and vibrating sample magnetometer, respectively. The XRD analysis confirms the creation of cubic crystalline structure with the crystallite size from 38 (x = 0.12) to 57 (x = 0.03) nm. The lattice constant of the ferrite nanoparticles is found to decrease with La content. Using XRD patterns, the development of a cubic crystalline structure was revealed. An increase in the amount of La3+ ions in Zn0.5Cr0.5LaxFe2-xO4 nanoferrites could explain the decrease in crystalline size. In Zn0.5Cr0.5LaxFe2-xO4 nanoferrites, impedance investigation revealed the presence of pseudo-capacitance and resistive behavior. The conductivity of Zn0.5Cr0.5LaxFe2-xO4 nanoferrites was also slightly reduced when La3+ ions were added. The soft ferromagnetic behavior of Zn0.5Cr0.5LaxFe2-xO4 nanoferrites was aided by the hysteresis loops. An increase in the La content of Zn0.5Cr0.5LaxFe2-xO4 nanoferrites resulted in a decrease in saturation magnetization and an increase in coercivity.