Dielectric behaviour in Ni0.65Zn0.35CuxFe2.xO4 ferrites

Abstract

A series of samples of the type Ni0.65Zno.35CuxFe2-xO4 (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5) were prepared by means of a ceramic technique. The existence of a single phase was confirmed in X-ray studies. The dielectric constant K and dielectric loss D were measured at different temperatures at a frequency of 1 kHz. The pronounced increase in the dielectric constant at the transition temperature is due to the phase transformation from the ferrimagnetic to the paramagnetic state. The decrease in the dielectric loss with temperature is due to the reduction in the relaxation time of the hopping electrons and holes. The Tawfik constant was calculated in the ferrimagnetic state and was found to be correlated to the dielectric constant.The polycrystalline ferrites are good dielectric materials. The dielectric properties of ferrites depend on many factors, including the sintering temperature and the preparation conditions. Ferrites have low conductivity, which is one of the reasons for their microwave applications.Many investigators have studied the dielectric properties of Ni-Zn ferrites [1], Mn-Zn ferrites [2,3], Mn-Mg ferrites [4] and Li-Ni ferrites [5]. The measurements [4,5] were carried out at room temperature in the frequency range 102 to l0 s Hz. It was found that e, e and tan 6 decrease with increasing Ni content in Li-Ni ferrites [5]. The value of the measured dielectric constant e was found to be of the order of 105. These results were explained on the basis of the model published in [5]. The same value of the dielectric constant was found for Mn-Zn ferrites [6]. The reported value for the dielectric constant at 103 Hz was 17, while the a.c. conductivity was 10.2-10 -9 ~,-~-1. cm-1 for Coo.49Zno.51Fe204 [7].

Structural, dielectric and magnetic properties of NiCuZn ferrite grown by citrate precursor method

“…Hence, the variation in dielectric constants could be attributed to the effect of variations in the simultaneous contributions of the different factors depending upon the composition. Similar trends in dielectric constant as a function of composition have also been reported earlier [20]. The dielectric constant is found to decrease with increase in frequency.…”

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

“…The introduction of Cu z+ ions into the lattice results in a decrease in the number of Fe 3+ ions at octahedral sites, which increases the lattice strain. The pronounced increase in the density of the ferrite [12] minimizes the lattice strain, leading to high Y. For increasing x up to 0.3, the oxygen vacancies accelerate densification during sintering [13].…”