Hydrothermal synthesis of Ce/Zr co-substituted BiFeO3: R3c-to-P4mm phase transition and enhanced room temperature ferromagnetism

Abstract

A facile hydrothermal method was used for fabricating phase-pure Bi1-xCexFe1-xZrxO3 (x = 0.00, 0.03, 0.06) multiferroic ferrites, and the dependence of structural, optical, and magnetic properties on the composition have been investigated. The samples were investigated by X-ray diffraction (XRD), Raman and Fourier-transform infrared (FT-IR) spectroscopies, scanning electron microscopy, UV-Vis spectroscopy, and vibrating sample magnetometer at room temperature. Structural results show that the structure of Bi1-xCexFe1-xZrxO3 ferrites is indexed to a rhombohedral structure with R3c space group. However, the weakening in the intensity, the expansion of the line-width of all bands, and some band shifts observed in Raman spectra indicate a structural transition from rhombohedral (R3c) to pseudo-tetragonal (P4mm) phase as the content of Ce/Zr increases. Also, a significantly enhanced intensity of the A1-2 mode in Raman spectra means that there is a novel behavior of magnetic anisotropy in the Ce/Zr cosubstituted samples. A significant increase in optical band gap with increasing of the Ce/Zr cosubstitution suggests that the materials are suitable for technological applications. Magnetic properties of the samples show a magnetic transition from antiferromagnetic to ferromagnetic phase due to the presence of the rhombohedral to the tetragonal phase transition, and exchange interaction between the 4f orbitals of the Ce 3+ /Ce 4+ and the 3d orbitals of the Fe 3+ /Fe 2+ .

Effect of heavy rare‐earth substitution on physical properties of BiFeO3 thin films and their photocatalytic application

“…The photocatalytic removal efficiency of dye 𝜂 is calculated as 14,43 $$$$\begin{equation}\eta \ = \frac{{{C}_0 - C}}{{{C}_0}}\ \times 100\end{equation}$$$$…”

“…For example, cerium (Ce), and to a much lesser extent Pr and Tb, can form RE 4+ ions, and Sm, Eu, and to a lesser extent Yb can form RE 2+ ions. These deviations from "normal" behavior (formation of only RE 3+ ) are sometimes attributed to the special stability of empty, half-filled, or filled shells: Ce 4+ (4f • ), Eu 2+ (4f 7 ), Yb 2+ (4f 14 ), but Pr 4+ (4f 1 ) and Sm 2+ (4f 6 ) do not fully satisfy this criterion. The results of our structural investigations indicate the shrinkage of unit cell volume.…”

“…Therefore, it can be concluded that doping of the BiFeO 3 with the rare-earth substitutions is one possible way to improve the photocatalytic properties of BiFeO 3 . [13][14][15][16][17][18][19][20][21][22][23] Dhanalakshmi et al 24 prepared Bi 1−x R x FeO 3 (R = Ce, Tb, x = 0.1) nanostructures with nano-rodlike morphology and rhombohedral to orthorhombic structure. They used prepared nanostructures as a catalyst in the photodegradation of phenol red, and they reported the degradation efficiency of about 85%-97% under visible light in the presence of magnetic fields.…”

“…Studies demonstrated that using the rare‐earth substitution at the Bi site can modify the crystal structure, morphology, and band‐gap energy of BiFeO 3 . Therefore, it can be concluded that doping of the BiFeO 3 with the rare‐earth substitutions is one possible way to improve the photocatalytic properties of BiFeO 3 13–23 . Dhanalakshmi et al 24 .…”

Exchange-spring behavior in Ni0.3Cu0.2Zn0.5Fe2O4/PbFe12O19 nanocomposite

“…The ferrimagnetic ferrites can be divided into three families based on their resistance to being demagnetized (magnetic coercivity): soft [1], intermediate [2], and hard [3]. They can be classified into four categories based on their crystal structures: spinel ferrite [4], hexaferrite [3], garnet ferrite [5], and orthoferrite [6,7].…”