Propriedades magnéticas e elétricas da Ferrita de MgGa(2-x)FexO4

Abstract

The ceramics of the type ferrites are materials that present important characteristics of electrical conduction and magnetic properties, as much as material magnetic hard, how much of soft magnetic materials. The cubics ferrites of the espinel structure are oxides with chemical formula MFe2O4, where M is a divalent metallic ion. Due to characteristic of the espinel, diverse magnetic configurations are a gotten, depending on the occupation tax of the magnetic ion (in general iron) in each sublattice. The diluted ferrites possess general formula given for: MD2-xFexO4, where M and D are diamagnetics ions, being D the ion of substitution doping and x is the concentration of ions of iron (0,002 ≤ x ≤ 0,350). The sample was prepared using ceramics techniques in reaction of solid state and later they were submitted to a magnetic characterization, electric and X-ray diffraction. The results of the magnetic characterization were gotten by a magnetometer of vibrant sample (VSM) EG&G-Princeton Applied Research, model 4500; the characterization for X-ray was used one X-ray diffractometer, model URD 65; of the Seifert & with. Electrical measurements DC were carried through with the use of a unit high-voltage measuring source - Keithley, model 237, where the voltage applied in the samples varied of 0–40 V, the high temperatures. Two types of contacts were used: the arrangement type "sandwich", being the inferior electrode the proper door-sample, and the superior electrode with ring geometry and a silver was pasted on both sides of the samples to ensure good electrical contact. The magnetic measurements confirm its ferrite characteristics and in the electrical measurements, the electrical conductivity indicated behavior of a semiconductor the high temperatures and the process of electrical conduction termically presented to be activated