The effect of Nd and Zr co-substitution on structural, magnetic and photocatalytic properties of Bi1-xNdxFe1-xZrxO3 nanoparticles

In this paper, Bi1-xNdxFe1-xZrxO3 (x = 0.00, 0.02, 0.04, 0.06, 0.08, 0.10) nanoparticles were prepared by citrate-nitrate method. The samples were structurally and magnetically characterized by X-ray diffraction, field-emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectrometry (FT-IR), trans-mission electron microscopy, and vibrating sample magnetometer. Structural analysis of the samples shows a rhombohedral structure (space group R3c) for samples x = 0.00, 0.02, 0.04, 0.06, while two lattice structures of the rhombohedral phase and cubic (space group Fd-3m) coexist for samples x = 0.08, 0.10, as confirmed by FT-IR spectrometry. FE-SEM images show that the average particle sizes of 50-100 nm have decreased with increasing Nd/Zr concentration. The magnetic properties of the samples such as the coercive field, remanence magneti-zation, and saturation magnetization indicate a hard ferromagnetic behavior compared to the antiferromagnetic behavior of the BiFeO3. The better magnetic properties observed for sample x = 0.08 than other synthesized samples can be mainly attributed to the destruction of the periodicity of spin cycloid by the structural phase transition, the reduction of particle size, uncompensated surface spins in the nanoparticles, decrease in the Fe-O-Fe superexchange interaction, and to the exchange coupling between Nd3+ and Fe3+ ions. Also, sample x = 0.08, show the best photocatalytic activity (similar to 92%) among the samples and much higher than that for the pure BFO sample (similar to 48%), which can be attributed to the smaller average particle size.