A novel low-temperature preparation of Ni-Zn ferrite and the properties of the ultrafine particles formed

Abstract

Ultrafine particles of nickel-zinc ferrite have been formed from solutions of metal nitrates by coprecipitation with hydrazine, foHowed by aging at 90 DC. The crystallites either aggregate into much larger dusters or form single particles, depending upon the preparation conditions, and vary in size from 30 to z 300 A. Saturation magnetizations (Ms) of the ferrites varied from 40 to 65 emu/g and the coercivities from 1 to z 100 Oe. Increasing hydrazine concentrations tended to produce particles with lower M,. However, for hydrazine/metal ratios below unity, decreasing the hydrazine concentration dramatically lowered the M, value. Particles formed without hydrazine (e.g., by aging hydroxides precipitated with potassium hydroxide) did not appear to be magnetic. Variations of the magnetic properties and lattice parameters as a function of preparation conditions will be discussed.3786

Magnetic and Mössbauer spectroscopic studies of NiZn ferrite nanoparticles synthesized by a combustion method

“…Saturation of magnetization is observed above a field of 5 kOe for the samples annealed above 1,000 K [13]. The saturation magnetization obtained for the sample annealed at 1,073 K is found to be higher than those reported for low-temperature synthesized samples annealed above 1,273 K [9,14], as well as comparable to that of the commercial bulk samples sintered at 1,673 K [15,16]. Figure 2 shows the variation of the saturation magnetization of the NiZn ferrite samples as a function of the particle size.…”

Ionic disorder and Yaffet–Kittel angle in nanoparticles of ZnFe2O4 prepared by sol‐gel method

“…Because the magnetic properties of nanoparticles are of great current interest, techniques are being developed to produce various magnetic nanoparticles. Several methods such as co-precipitation, sol-gel, hydrothermal process and ball milling have been reported to successfully synthesize ferrite nanoparticles [1][2][3][4]. It is known that there are two sites, A (tetragonal) and B (octahedral), in the spinel ferrite MFe 2 O 4 .…”

Structural, dynamic magnetic and dielectric properties of Ni0.15Cu0.2Zn0.65Fe2O4 ferrite produced by NaOH co-precipitation method

“…However, stoichiometric compositions cannot be well controlled by conventional ceramic processes, and impurities would be introduced during ball-milling. Wet chemical methods such as co-precipitation using mixed metal nitrates by hydrazine [11] and sol-gel method [12] have overcome these drawbacks and produced homogeneous, fine and reproducible ferrite powders. But these methods also brought the air pollution during decomposing at several hundred Celsius degrees.…”