Electrical and Magnetic Characterization of Multiferroic Composites

Abstract

newline Multiferroism refer to any combination of ferroelectric and magnetic order parameters in single phase as well as in artificial composites. The coexistence of several interactions, particularly existence of a cross-coupling between ferroelectric and magnetic orders, known as magnetoelectric (ME) coupling , brings about novel physical phenomena and offer possibilities for new multifunctional devices such as sensors, transducers, memories and spintronics. Observation of ME coupling in a material implies that the electric polarization/magnetization can be induced by application of magnetic/electric field; are termed as direct and converse ME effect respectively.. Among various non-lead based multiferroic composites, Bi based multiferroic composites are most extensively studied. Recently, there is a surge in research on Bi based material e.g., (Bi1/2Na1/2TiO3) BNT to be used as a ferroelectric/piezoelectric component for preparation of multiferroic composites. Therefore thesis focuses on the development of non lead Bi based multiferroic composites. In this work, studies based on sol-gel driven different multiferroic particulate composite series are presented. newline newlineThe thesis is organized into four chapters Chapter I (Introduction and Literature Review) newlineThis chapter gives a brief introduction and historical developments about the multiferroic materials and need or advantages of the Multiferroic materials. The appropriate definitions of various terms related to the field (e.g, definitions of multiferroics, magnetoelectric coupling coefficient, types of multiferroicity) are given. Multiferroic materials are classified on the basis of single phase as well as composite structures. Further, composites are classified on the basis of lead and non lead based composites. Finally the different connectivity schemes of composites have been discussed. newlineChapter II (Experimental and characterization techniques) newlineThis chapter gives details the processing methods employed for synthesizing the samples of different compositions. A brief detail of the various characterization techniques used to study structural, microstructural, dielectric, ferroelectric, magnetic and magnetoelectric properties are provided. newline newlineAbstract newline newlineChapter III (Results and discussion) newlineIn this chapter, the experimental results of the synthesized samples of different multiferroic composite series are presented. The effect of addition of weight ratio of ferrites in BNT and modified BNT based ferroelectric matrix has been studied on their structural, dielectric, magnetic and ferroelectric properties. newlineChapter IV (Conclusions and future scope) newlineThis chapter gives an important conclusions and future scope in this field of research newline