Effect of cobalt substitution on the properties of nickel–copper ferrite

Abstract

Cobalt-substituted nickel–copper ferrite samples having the chemical formula Ni0.95−xCoxCu0.05Fe2O4, where x varies as 0.01, 0.02 and 0.03, were prepared by the standard double sintering ceramic technique. The formation of the ferrite phase was confirmed by x-ray diffraction (XRD) studies. Resistivity and thermo-emf variation with temperature were studied in the temperature range from room temperature to 773 K as a function of cobalt content. As the cobalt content increases, the resistivity of the ferrites decreases. AC conductivity measurements made in the frequency range 100 Hz–1 MHz show that conduction in these ferrites is due to small polaron hopping. The dielectric constant and loss tangent (tanδ) were measured at room temperature as a function of frequency in the range 20 Hz to 1 MHz. The room-temperature dielectric measurements show dispersion behaviour with increasing frequency. To understand the conduction mechanism, complex impedance measurements were carried out. The variation in saturation magnetization (Ms) with variation of cobalt content is also studied.

Structural, electrical and magnetic properties of cadmium substituted nickel–copper ferrites

“…The wide applications of ferrites in various fields created an interest to study the electric and magnetic properties such as high saturation magnetization, stability, resistivity and low loss energy over a wide range of frequency [1][2][3]. The substituted nickel ferrites are the subject of extensive investigation because of their microwave applications such as circulators, isolators, phase shifters, etc., due to its low electrical conductivity, squareness of hysteresis loop [4,5].…”

“…The lattice parameter increases due to the increase of cadmium content in the ferrites because of its higher ionic radius compared to other ions in the ferrites. Several researchers have studied the structural, electrical and magnetic properties of substituted ferrites like Ni-Co-Cu [1], Ni-Cd-Zn [12], Ni-Cd [11,[13][14][15], Ni-Cu [16], Mg-Cd [17] and Ni-Mn-Mg [18] mixed ferrites by different methods. However, the literature survey on Ni-Cd-Cu ferrites indicates that not much work has been done on these ferrites.…”

Microstructure, AC impedance and DC electrical conductivity characteristics of NiFe2-xGdxO4 (x = 0, 0.05 and 0.075)

“…[12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] However, the efforts towards understanding the effect of the substitution of rare earth (R) ions in spinel oxides are meager. Engineering the materials and development of devices for high frequency applications based on nickel ferrites is clearly dependent upon the fundamental knowledge of electrical behavior of these materials.…”

Annealing temperature effect on structural and magnetic properties of nano crystalline Ni0.6Co0.2Cu0.2Fe2O4 (NCCFO) thin film

“…The maximum value of saturation magnetization is observed at 850 0 C (168.3emu/cc). The values of saturation magnetization are higher than that for NCCFO ferrite pallets synthesized by double sintered ceramic reaction technique reported by others [6]. The coercivity initially increases up to 750 0 C (1007.12 Oe) and then show sudden decrease for 850 0 C (701.52 Oe).…”