Nickel ferrite, NiFe2O4 was prepared by a soft mechanochemical route from a mixture of (1) Ni(OH)(2) and alpha-Fe2O3 and (2) Ni(OH)(2) and Fe(OH)(3) powders in a planetary ball mill for 25 h. The powder samples were sintered at 1100 degrees C for 2 h and were characterized by X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM). Impedance spectroscopy techniques were used to study the effect of grain and grain boundary on the electrical properties of the prepared samples. A difference in dielectric constant (epsilon) and dielectric loss tangent (tan delta) of NiFe2O4 samples obtained by the same methods but starting from different initial components was observed. (C) 2013 Elsevier Ltd. All rights reserved.