Structural Magnetic and Magneto Dielectric Response of La3 modified PbTiO3 and CoFe2O4 Composites

Abstract

The coexistence of ferroelectric and magnetic orders in single phase is a challenging task due to contradictory behavior of both. So mixed perovskite approach i.e mixing of dG and d-o ions has been adopted to synthesize the multiferroic solid solutions. It is evident from the review of literature that among all the ferroelectrics, PbTiO3 (PT) is the promising candidate for the synthesis of mixed perovskite solid solutions having multiferroic properties. PbTiO3 exhibits excellent ferroelectric and insulating properties such as spontaneous polarization, dielectric and high ferroelectric transition temperature whereas Co2FeO4 is another perovskite belonging to the family of rare earth orthoferrite. It exhibits G-type antiferromagnetic ordering having Neel temperature in between Tn_62K to 74K. So in the present research work, we have selected the La3+ Modified PbTiO3 Pb0.75La0.25TiO3 solid solutions and Composites of (1-x)(Pb0.75La0.25)TiO3 xCoFe2O4solid solutions system as a potential candidate to explore the multiferroic properties. In this system Fe3+ has been selected as B-site magnetic ion dopant which induces magnetic behavior along with increase in leakage current whereas La3+ is selected as A-site rare earth dopant to minimize the leakage current arising due to the substitution of Fe3+ ion at Ti4+ site. The magnetic materials, which as generally selected in mixed perovskite approach are antiferromagnetic materials. However, the magnetic properties of the antiferromagnetic materials need to be modified. So we have also tailored the magnetic properties of antiferromagnetic materials (LaFe2O4) by creating the charge imbalance with the aliovalent substitution of different ions (ions having different valence streej to both A and B-site For this Pb2+ and Ti4+ ions were selected as dopants at both A and B site of LaFeO3. In this thesis, we also studiedthe effect of Asite Pb2+ and B-site Ti4+ substitution on the structural, magnetic and newline