Effect of pH of the Reaction Medium on the Structure and Properties of Spinel-Type Ferrite Nanopowder

<span>In this work by using sol-gel auto-combustion synthesis was synthesized single-phase magnesium-substituted lithium ferrite at different pH reaction medium. The synthesized materials were investigated by X-ray and Mossbauer methods. It was shown that the pH of the reaction medium plays a crucial role in the formation of the microstructure and properties of synthesized systems. Nanosize particle of magnesium-substituted lithium ferrites </span><img src="http://www.pu.if.ua/inst/phys_che/start/pcss/vol18/img1.gif" border="0" alt="" /><span>were synthesized using sol-gel autocombusting method. Structural characteristics of the samples were received by using X-ray diffraction (XRD) and SEM (emission electron spectroscopy) analysis. XRD research confirmed that single phase spinel structure with crystallite size in the vicinity of 15 – 30 nm were formed. M-H loop was recorded using ferometra F-64. For all compositions were received hysteresis settings at room temperature and 50 Hz. Hysteresis loop of the samples showed a clear saturation at appositional field 60 ± E and by nature is very symmetrical. Dielectric parameters such as dielectric constant </span><span>resistivity ( </span><img src="http://www.pu.if.ua/inst/phys_che/start/pcss/vol18/images/anote1801_16ae_htm_anote1801_16a_htm_eqn8754.gif" border="0" alt="" /><span>and </span><img src="http://www.pu.if.ua/inst/phys_che/start/pcss/vol18/images/anote1801_16ae_htm_anote1801_16a_htm_eqn8811.gif" border="0" alt="" /><span>) and samples conductivity </span><span>investigated as a function of the frequency range from 0.01 Hz to 100 kHz in the temperature range 293 – 493 K using the impedance spectrometer. Dielectric constant of samples revealed normal dielectric dependent on frequency, which says that the dispersion is a consequence of the grain Maxwell-Wagner-type boundaries polarization and electron hopping between ions Fe</span>²⁺<span>and Fe</span>³⁺<span>. </span><br /><strong>Keywords:</strong><span> spinel, ferrite, combustion synthesis, microstructure.</span>