Synthesis and characterization of multiferroic composite Na0.5Bi0.5TiO3-CoFe2O4

Abstract

Multiferroic materials, which have been investigated extensively by the scientific community due to their multifunctionality, may present two or more physical properties of high technological interest. These materials have properties of both electric and magnetic ordering and exhibit an extraordinary potential for application in and optimization of devices based on ferroelectric and ferromagnetic materials and for the control of properties through the application of electric and magnetic fields. However, these intriguing properties are observed in a single phase in only a few systems, in which magnetoelectric coupling usually occurs under extreme conditions, such as very high magnetic fields and/or very low temperatures. The most relevant scientific evidence has been presented by materials in which two or more phases coexist. Recently, these materials have been obtained by two routes, which have yielded materials with different characteristics: solid state reactions using high temperatures and/or mechanical mixing, and chemical methods, which offer the possibility of obtaining materials at the nanometric scale. Previous studies in our laboratory have shown that it is possible to obtain homogeneous nanostructured materials devoid of unwanted phases with a good control of the synthesis parameters by the chemical method. In this project, we propose to prepare multiferroic ceramic composites with a magnetic phase consisting of cobalt ferrite and a ferroelectric phase composed of NBT, thus forming (Na,Bi)TiO3 - CoFe2O4. The relevance of this work is therefore tied to the need to develop new devices, by means of the one-step synthesis of a little understood and environmentally friendly (lead free) composite for future application of the powder in the manufacture of bulk nanoparticle ceramics with magnetoelectric properties.