Mechanical and electrical properties of Ni0.65Zn0.35CuxFe2−xO4 ferrite

A series of samples in the system Ni_0.65Zn_0.35Cu_xFe_2?xO₄ (x=0.0, 0.1, 0.2, 0.3, 0.4 and 0.5) were prepared by the usual ceramic technique. X-ray analysis showed that they were cubic spinel (single phase). Young's modulus, the dielectric loss and the change in capacitance under mechanical stress were measured for the samples. Young's modulus decreased with increasing Cu content. This is due to the fact that Cu²⁺ ions entered the lattice substitutionally for Fe³⁺ ions at the octahedral sites, creating lattice vacancies gave rise to lattice strain. The minimum value of the dielectric loss corresponding tox=0.3 may be due to the formation of lattice vacancies retarding the jump frequency to be far from the frequency of the applied a.c. field. The increase in capacitance of the samples with mechanical stress may be explained via the mechanism of dielectric polarization.