Nanopartículas de ferritas ZnxMg1-xFe2O4: estudo das propriedades estruturais e magnéticas em altas temperaturas

Abstract

In this work we have studied the crystalline structure and magnetic properties of the ZnxMg1−xF e2O4 ferrites, where the Znx concentration varied from 0 ≤ x ≤ 0.8. The samples were synthesized by the combustion reaction method, iron nitrate F e(NO)3.9H2O3, magnesium nitrate Mg(NO3)36H2O, zinc nitrate Zn(NO3)3.6H2O and urea CO(NH2)2 as the fuel. The ferrite were analyzes using X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS), vibration sample magnetome- try (VSM), Mössbauer spectroscopy and Raman spectroscopy. The X-ray diffraction showed the formation of spinel phase without spurious pha- ses. We also obtained the structural parameters through the Rieveld refinement method. The crystallite size varied from 37 nm to 55 nm for the samples with concentration of x = 0.88 and x = 0.4 respectively. With Mössbauer and Raman spectroscopy, we analy- zed the distribution of the cations in the ferric ZnxMg1−xF e2O4 with the substitution of magnesium for zinc, showing that zinc ions occupy the tetrahedral site. We obtaind the magnetic saturation, coercivity,and remanent magnetization through the vibrating sample magnetometer, and we verified that they varied with the amount of zinc.The ferrites had a maximum value of magnetic saturation of 246.4 emu/cm3 . The value of coercivity and the remaining magnetization decreased with the replacement of magnesium with zinc. The coercivity ranged from 82.0 Oe to 3.8 Oe to x = 0.0 and x = 0.8 respectively the remaining magnetization ranged from 17.0 emu/cm3 to x = 0.0 to 0.3 emu/cm3 to x = 0.8. We analyzed the magnetic behavior with the temperature variation and found that the Curie temperature decreased with the replacement of magnesium by zinc, and the Curie temperature of the magnesium ferrite, MgF e2O4 was 611 K. We studied the interaction between the grains through the Henkel plot and found that the interaction between them is of a dipole nature.