Study of the origin of ferroic properties using crystal and electronic structures in BiFeO3-based compositions.

Multiferroic materials with magnetoelectric properties, due to their coupling between the electrical and magnetic properties have attracted the attention of many researchers. Perovskite structured materials based on BiFeO₃ are a class of materials largely considered in these studies. In this work, Bi_1-xNd_xFe_0.99Co_0.01O₃ (x = 0.05, 0.10 and 0.20) compositions were synthesized aiming a better understanding of the crystal and electronic structure role in ferroic properties of these materials. Structural studies were made by X-ray diffraction and Rietveld refinement; evidencing the rhombohedral symmetry of the samples with space group R3c. Electron density calculations were performed by the maximum entropy method. These studies showed that Nd³⁺ substitution causes distortions in the unit cell, which have influence on the magnetic properties. Also, the electron density maps showed the bonds between the iron and oxygen ions did not changed a lot. But the Minimum Electron Density observations were enough to conclude that the ferroelectric and the dielectric properties of Bi_1-xNd_xFe_0.99Co_0.01O₃ compositions would be modified with the Nd³⁺ substitution. [ABSTRACT FROM AUTHOR]