Enhanced Multiferroic Properties of YFeO(3) by Doping with Bi(3+)

Tthe present work studied the cationic substitution of Y(3+) by Bi(3+) on the crystal structure of orthorhombic YFeO(3) and its effect over magnetic, dielectric and electric properties of multiferroic yttrium orthoferrite. Stoichiometric mixtures of Y(2)O(3), Fe(2)O(3) and Bi(2)O(3) were mixed and milled for 5 h using a ball to powder weight ratio of 10:1 by high-energy ball milling. The obtained powders were pressed at 1500 MPa and sintered at 700 °C for 2 h. The test samples were characterized at room temperature by X-ray diffraction (XRD), vibrating sample magnetometer (VSM), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS) and impedance spectroscopy (IS). The X-ray diffraction patterns disclosed a maximum solubility of 30 % mol. of Bi(3+) into the orthorhombic YFeO(3). For higher concentrations, a transformation from orthorhombic to garnet structure was produced, obtaining partially Y(3)Fe(5)O(12) phase. The substitution of Bi(3+) in Y(3+) sites promoted a distortion into the orthorhombic structure and modified Fe-O-Fe angles and octahedral tilt. In addition, it promoted a ferromagnetic (FM) order, which was attributed to both the crystal distortion and Dzyaloshinskii-Moriya interaction. For doped samples, an increase in real permittivity values was observed, and reduced with the increase of frequency. This in good agreement with the Maxwell-Wagner effect.