Structural and Magnetic Features of Mn_1-xZn_xFe₂O₄Nanoparticles

Abstract

This paper reports on the magnetic properties of Mn1−xZnx-ferrite nanoparticles. Dierent x compositions of the magnetic material have been considered. Field-and temperature-dependent magnetization curves and electron paramagnetic resonance (EPR) at dierent temperatures were used to reveal the magnetic properties of the samples. For x = 0.5, the EPR spectra consist of a single resonance signal, strongly symmetrical, with g = 3.25 close to 2073 G, and an asymmetric line corresponding to g = 4.4 for x = 0. The asymmetry is attributed to a random distribution of the anisotropy in the system, with perpendicular and parallel modes, giving information about the eective anisotropy of the system. For high concentrations, the resonant eld shifts to 2875 G. Magnetization measurements as function of temperature at 60 Oe according to the standard zero eld cooling (ZFC) and eld cooling (FC) procedures are reported. The behavior of eld cooling magnetization (MFC) at low temperatures evidences the presence of strong interparticles interactions.

Structural, Magnetic Properties and Electron Paramagnetic Resonance for BaFe12-xHgxO19Hexaferrite Nanoparticles Prepared by Co-Precipitation Method

“…The increase in x pp reflects the strengthening of the dipolar interaction and indicates the existence of critical grain size with 0.00 ≤ x ≤ 0.10 as the crystalline size increases up to x = 0.10. On the other hand, the decrease in x pp for x ≥ 0.20 can be interpreted as the reduction of magnetic interaction effect, according to the reduction of magnetic ions (Fe 3+ ions), confirming with the model of solid solutions with magnetic dilution; x pp ∝ (1 − x) 1/2 [51]. The number of spins N participating in the resonance are estimated from comparing the area under the absorption curve with that for CuSO 4 .5H 2 O [50].…”