Synthesis and characterization of cobalt based ferrite

• Auteur principal: A. Ati, Ali
• Format: Thèse
• Langue: anglais
• Publié: 2015
• Sujets: QC Physics
• Accès en ligne: http://eprints.utm.my/61080/1/AliAATIPFS2015.pdf

Magnetoelectric (ME) materials have the ability to convert magnetic energy into electrical energy and/or vice versa. This work involves the study of structural, electrical and magnetic properties of (f)Ni(1-x)(Co/Mn)xFe2O4/Pb(Mg0.33Nb0.67)0.67 Ti0.33O3 nanocomposites, which have been successfully synthesized by chemical co-precipitation method. The presence of both phases in the composites were confirmed by using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and vibration sample magnetometer (VSM). The variations of dielectric constant and loss tangent as a function of frequency as well as temperature were studied using two-point probe impedance analyzer. Temperature dependent dielectric constant shows diffused phase transition in magnetoelectric nanocomposites. The DC electrical resistivity measurements were carried out within the temperature range of 300 – 923 K. Variation of magnetoelectric voltage coefficient traces the path of magnetostriction as a function of magnetic field. All composites show peak behavior in magnetic field dependent on magnetoelectric voltage coefficient. The magnetoelectric (ME) powder nanocomposite system of (f) Ni(1-x)(Co/Mn)xFe2O4+ (1-f) Pb(Mg0.33Nb0.67)0.67Ti0.33O3 (with x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) and f = 0.15, has been successfully studied. The magnetoelectric coefficient for all the composites were measured using static magnetoelectric set up. All magnetic field dependent of magnetoelectric measurements show peak behaviour, which can be explained on the basis of magnetic field dependent variation of magnetostriction and piezomagnetic coefficient behavior. The strong compositional dependent of magnetoelectric voltage coefficient is a common feature for ferrite base nanocomposites. In this study the magnitude of the magnetoelectric coefficient is found to be higher with increasing amount of ferrite phase in nanocomposites samples. The magnetoelectric studies show that high resistive magnetic phase with high piezomagnetic coefficient in low magnetic field region is helpful to enhance the magnetoelectric coupling. The present data suggest that the magnetoelectric interaction depends on the magnetostriction behaviour, piezomagnetic coefficient, resistivity, content of constituent phases and connectivity between the phases.