Structural, dielectric and magnetic properties of Bi sub(1-x)Y sub(x)FeO sub(3) (0 [< or =, slant] x [< or =, slant] 0.2) obtained by acid-base co-precipitation

Bismuth-iron oxides with partial substitution of bismuth by yttrium, referred as (Bi sub(1-x)Y sub(x))FeO sub(3), were synthesized by simple-low cost acid-base co-precipitation method, which constitutes a difference with the currently used synthetic methods for obtaining BiFeO sub(3)-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 (Y) substitution on magnetization curves of (Bi sub(1-x)Y sub(x))FeO sub(3) 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, H sub(c) 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-1MHz and the results were successfully fitted by a simple parallel R-C model. The dc-leakage currents are lower than previously reported for (Bi sub(1-x)Y sub(x))FeO sub(3) compounds and for most of the doped-BiFeO sub(3) 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.