HIGH Tc MULTIFERROICS WITH NARROW BAND GAP

Abstract

Research into multiferroicity has increased dramatically in recent years. Following this area of research, present work investigates the multiferroic properties of Potassium Bismuth ferrite (KBiFe2O5) , Sodium Bismuth ferrite (NaBiFe205) and Lithium Bismuth ferrite (LiBiFc2O5) .The starting materials were potassium carbonate (K2CO3) , Lithium carbonate (Li2CO3), sodium carbonate (Na2CO3), Bismuth(II!)oxidc (Bi203) and Iron oxide (Fe2O3). Multiferroic ceramics were prepared by solid state reaction method. Sodium Bismuth ferrite (NaBiFe205) and Lithium Bismuth ferrite (LiBiFe205) were calcined at 6000C, 6500C and 650C respectively for two hours. Purity and phase formation of particular compounds have been confirmed by X-ray diffraction at room temperature. The pellets were sintered at 7000C for two\ - hours. We observed ferroelectric transition at 3550C, 3550C and 5150C for LiBFO, NaBFO and KBFO respectively. We observed weak ferroelectric and\ magnetic properties of all ceramics. We also observed a small band gap ( 2\ eV) for all ceramics which is required for photovoltaic application.