Structural, dielectric and magnetic properties of Bi(1−x)YxFeO3 obtained by acid?base co-precipitation?

SALEH MEDINA, L.M.; JORGE, G.; NEGRI, RICARDO MARTÍN

JOURNAL OF ALLOYS AND COMPOUNDS

ELSEVIER SCIENCE SA

Lugar: Amsterdam; Año: 2014 vol. 592 p. 306 - 312

0925-8388

Bismuth-iron oxides with partial substitution of bismuth by yttrium III, referred as (Bi1- xYx)FeO3, were synthesized by simple-low cost acid-base co-precipitation method, which constitutes a difference with the currently used synthetic methods for obtaining BiFeO3-doped compounds (e.g. polymer assisted sol-gel, solid state, microwave, etc.) Samples were characterized by XRD, EDS, SEM, TEM, DSC and FTIR. The influence of yttrium III (referred as Y) substitution on magnetization curves of (Bi1- xYx)FeO3 powders were studied at room temperature by VSM. The particle size systematically decreases with the Y percentage. Ferromagnetic curves were obtained at room temperature for Y-percentage lower than 20% with relatively large values of the coercive field, Hc, which increases with Y-substitution, while for 20% yttrium a superparamagnetic behavior is observed. The electrical impedance of compressed disks were investigated also by impedance analysis in the range 1Hz-1 MHz and the results were successfully fitted by a simple parallel R-C model. The dc-leakage currents are lower than previously reported for Bi1- xYx)FeO3 compounds and for most of the doped-BiFeO3 ceramics. As a difference with the influence on the magnetic behavior, the doping with yttrium does not seem to have a large influence on the dielectrical properties. These results suggest that magnetization can be systematically modified by the relatively simple co-precipitation synthesis while keeping invariable the dielectrical properties. KEYWORDS: multiferroic compounds, bismuth-iron oxides, yttrium substitution, magnetization, impedance analysis.