Magnetoelectric coupling in complex oxides heterostructures

Abstract

The magnetoelectric multiferroic materials present the coexistence of ferromagnetic (anti-ferromagnetic) and ferroelectric orders and were widely studied in the decades of 60 and 70 in the bulk form. Nowadays, a growing interest is directed to the properties of these materials in the form of thin films (or nanostructured), mainly due to the possibility of applying such materials in micro-electronic devices. The coupling between the different ferroics orders is the main property in these materials because it could allow the control of electric polarization through the application of a magnetic field and, analogously, the control of magnetization by the application of an electric field. Materials with such coupling have potential to be applied as sensors or as media for non-volatile storage of information allowing the recording of information with a smaller energy consumption. This post-doc project aims the growth of nanostructured multiferroic materials in thin films form, nanostructured within magnetic/metallic multilayers. Subsequently the electronic structure characterization will beinvestigated by means of X-ray absorption spectroscopy and magnetic dichroism at PGM beam-line of the National Synchrotron Light Laboratory. Our goal is understand the mechanisms on the origin of the interaction between the two ferroic orders in this kind of materials. Such comprehension would allow the control on the desired properties - making viable the application of such materials in micro-electronic devices - or also could indicate new potential materials to be used in applications. This project aims initially the growth of perovskite thin films (BiFeO3 and BaTiO3) and later multilayers of these with metallic or magnetic materials (initially Co, Fe, NiFe e Pd) by sputtering technique. Furthermore, the collaboration with the Grupo de Cerâmicas Ferroelétricas (GCFerr) da Universidade Federal de São Carlos (UFSCar) intends the growth of composites of ferromagnetic ferrites (NiFeO3, CoFeO3) associated with ferroelectric materials like PbZrxTi(1-x)O3 with sputter targets produced on GCFerr-UFSCar.