Effects of Milling Atmosphere and Increasing Sintering Temperature on the Magnetic Properties of Nanocrystalline Ni_0.36Zn_0.64Fe₂O₄

Abstract

Nanocrystalline Ni0.36Zn0.64Fe2O4was synthesized by milling a powder mixture of Zn, NiO, and Fe2O3in a high-energy ball mill for 30 h under three different atmospheres of air, argon, and oxygen. After sintering the 30 h milled samples at 500°C, the XRD patterns suggested the formation of a single phase of Ni-Zn ferrite. The XRD results indicated the average crystallite sizes to be 15, 14, and 16 nm, respectively, for the 30 h milled samples in air, argon, and oxygen atmospheres sintered at 500°C. From the FeSEM micrographs, the average grain sizes of the mentioned samples were 83, 75, and 105 nm, respectively, which grew to 284, 243, and 302 nm after sintering to 900°C. A density of all the samples increased while a porosity decreased by elevating sintering temperature. The parallel evolution of changes in magnetic properties, due to microstructural variations with changes in the milling atmosphere and sintering temperature in the rage of 500–900°C with 100°C increments, is also studied in this work.

Structural, Electrical, Dielectric, and Magnetic Properties of Cd2+ Substituted Nickel Ferrite Nanoparticles

“…Usually, increasing crystallite size in ferrite nanoparticles decreases the magnetic property because a large grain size leads to a low signal to noise ratio [31]. X-ray density ( X ) was calculated using the relation [32]:…”

Morphological analysis of Cu substituted Ni\Zn in Ni-Zn ferrites

“…Generally, the single grain is the composition of several crystals. The grain size depends on the sintering temperature and atmosphere [19]. They can be from very small colloidal particles, clay, silt, sand, gravel, cobbles to boulders.…”

Magnetic Loss Decomposition in Co-Doped Mn-Zn Ferrites

“…As a first step of the loss analysis, we show that the dependence of Wh(Jp) on Co doping can be to good extent predicted. By posing in fact 𝑊 h (𝐽 p )  4H c 𝐽 p,dw , where Hc is the coercive field and Jp,dw = Jp dw,DC /(dw,DC + rot,DC) is the contribution by the dws to Jp, and by considering the inverse dependence of Hc on the average grain size <s> [Herzer 1997], a law expected to be valid for <s> larger than a few hundred nanometers [Hajalilou 2015], we get…”