Chemical substitutions in Bi₃Fe_0.5Nb_1.5O₉ related phases to enhance magnetic and electric properties

Victor P. Barbosa¹, Michael W. Lufaso²

Department of Chemistry, University of North Florida, 1 UNF Drive, Jacksonville, FL 32224

Bi₃Fe_0.5Nb_1.5O₉ adopts the Aurivillius structure and is recognized for its electronic and magnetic properties. The interactions between electronic and magnetic properties are of interest for advanced applications such as magnetoelectric (ME) devices; e.g., sensors that convert magnetic field variations into electric signals and vice versa. Bi₃Fe_0.5Nb_1.5O₉ has a ferroelectric transition near 255°C and is paramagnetic to 6 K. To investigate if those properties are tunable, a series of samples were synthesized where the similarly sized and charged lanthanum was substituted for bismuth in Bi_3‑xLa_xFe_0.5Nb_1.5O_{9 .} Well characterized materials are needed for electronic and magnetic properties measurements, therefore we used a powder X-ray diffractometer to identify the phases present in the samples and verify if the doped structures are isostructural. The Rietveld method was utilized in the determination of the purity, lattice parameters and crystal structures of the substituted samples. The effects of chemical substitution indicate anisotropic effects on the lattice parameters.