Efect of the heat treatment conditions on the synthesis of Sr-hexaferrite

RICARDO MARTÍNEZ GARCÍA; VITALIY BILOVOL; LEANDRO SOCOLOVSKY

Congreso; X encontro da SBMat; 2011

The effect of the heat treatment conditions under oxygen atmosphere on the SrFe12O19 (Sr-M ferrite) synthesis is analyzed. We study the effect of the partial evacuation of the gases of decomposition of the organometallic precursor on the phase composition of different samples. An accurate structural analysis of samples obtained between 250 º C (with Sr-M crystallite size, Ø, around 20 nm) and 500 º C (Ø ~ 40 nm) is reported. From the structural analysis two secondary phases, hematite and maghemite, are identified. The amount of secondary phases (between 10 % and 30 %) can be manipulated through the control of the heat treatment conditions, and therefore, this constitutes a methodology to manipulate the phase composition of the nanopowders. The influence of secondary phases on the magnetic properties of the samples is also studied. The quantitative determination of phases is performed by structural refinement of X-ray powder patterns, by using Rietveld analysis. Magnetic study is done by Magnetization vs Temperature and Magnetization vs Applied Magnetic Field.