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This article presents the production and structural and magnetic characterization of the Bi1-xYxFeO3 System x = 0 and 0.07. The samples were obtained by solid state reaction method and characterized by x-ray diffraction (XRD), electron microscopy scanning (SEM) and Mössbauer spectroscopy. The analysis by Rietveld refinement, allowed to determine that system Bi1-xYxFeO3 crystallizes in the Group R3c (161) rhombohedral. The obtained results allowed to conclude that the replacement of Bi by ions of and influence the appearance of Bi2Fe4O9 impurities, without affecting the structural response of the samples with the increase of doping yttrium. [ABSTRACT FROM AUTHOR]

Yttrium and rare earth manganites crystallize in two principal phases: hexagonal and orthorhombic. For ions with small atomic radii Y, Yb and Ho the typical crystallization is hexagonal and for Sm, which has a smaller atomic radii, the crystallization is in orthorhombic phase. The preparation of the compounds R1-xSmxMnO3 was performed by the standard solid state reaction technique. Determination of crystal structure, lattice parameters and bond angle reported for these manganates were developed in the Rietveld method's context. The pure perovskites RMnO3 cristallized in the space group P63cm, the lattice parameters a and c achieve 6 Å and 11 Å, respectively, while SmMnO3 structure crystallizes at the special group Pnma. Rietveld refinement revealed the effects of Sm into the pure hexagonal structures, evidencing crystallographic changes with ortorrombic trends for strong concentrations of Sm. [ABSTRACT FROM AUTHOR]

We discuss and describe the method to produce ceramic samples of bismuth manganate (BiMnO3). We display the characterization of the crystal structure using DRX. We performed measurements of capacitance and the loss factor (tan δ) as function of temperature as well as for the conductivity at different frequencies (from 20 Hz to 1MHz). It seems that there is a transition around 630K. Moreover, we made Polarization vs. Voltage measurements obtaining hysteresis loops at low and room temperatures. The results of this work can give rise to new evidences about the multiferroic properties of bismuth manganites. [ABSTRACT FROM AUTHOR]