Influence of Nd and Er substitution on magnetic and dielectric properties of bismuth ferrite (original) (raw)

Structural, Dielectric, and Magnetic Properties of Ba-Doped Multiferroic Bismuth Ferrite

The main focus of the research was to correlate the microstructure with dielectric and magnetic properties of Bi1-xBaxFeO3 samples. Bi1-xBaxFeO3 samples (x = 0.1, 0.2 and 0.3) were synthesized by the conventional solid-state reaction method using nano-powders of Bi2O3, Fe2O3, and BaCO3. Thereafter, field emission scanning electron microscope and X-ray diffraction (XRD) techniques were used to examine the structure and phase of the samples. Phase analysis by XRD indicated that the single-phase perovskite structure was formed with possible increment in lattice parameter with increasing Ba doping. Complex permeability (l0 i and l00 i ) measured using impedance analyzer confirmed the increase in magnetic property with increasing Ba doping. Finally, dielectric constant (k) was analyzed as a function of temperature at different frequencies. Dielectric constant as high as 2900 was attained in this research for Bi0.8Ba0.2FeO3 sample due to reduction in leakage current at this composition.

Change in structural, ferroelectric, and magnetic properties of bismuth ferrite induced by doping with gadolinium

Ceramics International, 2019

Bismuth ferrite, BiFeO 3 , was doped with a wide range of concentrations (0-30%) of Gd in order to investigate structural, ferroelectric, and magnetic properties and their correlation. Powder samples of Bi 1-x Gd x FeO 3 (x = 0.00-0.30) were prepared using the hydro-evaporation synthesis method. Sintering process at 870°C for 6 h of as-prepared, Gd doped BiFeO 3 powders resulted in ceramic samples with relative densities in the range of (74-86) %. XRD analysis revealed that Bi 1-x Gd x FeO 3 samples (x = 0.00-0.09) crystallized in rhombohedral phase; Bi 1-x Gd x FeO 3 samples (x = 0.10-0.20) contained both rhombohedral and orthorhombic phases, while Bi 1x Gd x FeO 3 (x = 0.30) sample contained only the orthorhombic phase. The structural parameters obtained after Rietveld refinement for single-phase Bi 1-x Gd x FeO 3 ceramic samples and microstructure image analysis were correlated with the results of ferroelectric and magnetic measurements. Bi 1-x Gd x FeO 3 (x = 0.0625, 0.075, 0.09) samples showed improved ferroelectric properties and reduced leakage current density in comparison with undoped BiFeO 3. Gradual increase in Gd content in BiFeO 3 led to enhanced magnetic responses and weak ferromagnetic behavior.

Effect of Mn substitution on dielectric and magnetic properties of multiferroic bismuth ferrite

Nanocrystalline powders of bismuth ferrite (BiFeO3) and manganese doped bismuth ferrite (Bi0.95Mn0.05FeO3) were prepared using sol-gel autocombustion method. Structural analysis of these samples using XRD data reveals the existence of rhombohedrally distorted perovskite phase in both the samples. The Mn doping for A-sites in bismuth ferrite improves the surface morphology with uniform grain growth as confirmed by scanning electron micrographs on the samples. The frequency responses of dielectric constant (ε) and dielectric loss tangent (tan δ) have been investigated in a wide range of frequencies at room temperature. Dielectric performance was improved in the manganese doped bismuth ferrite when compared to pure bismuth ferrite. Magnetic studies (M-H loops) were also carried out using vibrating sample magnetometer at room temperature in order to understand the magnetic behaviour of the materials. Significant enhancement in the value of saturation magnetization was found in the manganese doped bismuth ferrite system. The variations in different dielectric and magnetic parameters of the Mn doped bismuth ferrite have been understood in terms of the modified cationic preferences and structural changes. Nevertheless, it can be inferred that the improved results in structural, dielectric and magnetization values in the manganese doped system would obviously make it a good choice for sensors and actuators applications.

Investigation of structural, magnetic and optical properties of rare earth substituted bismuth ferrite

Journal of Rare Earths, 2013

Polycrystalline BiFeO 3 and rare earth substituted Bi 0.9 R 0.1 FeO 3 (BRFO, R=Y, Ho and Er) compounds were prepared by rapid solid state sintering technique. Structural phase analysis indicated that all the compounds stabilized in rhombohedral structure (R3c space group) and a small orthorhombic phase fraction was observed in BRFO compounds. From the Raman spectra results, the changes in the phonon frequencies (A 1 ) and line widths suggested lattice distortion in the BRFO compounds as was evidenced in the XRD analysis. Compared to the linear variation of magnetization with magnetic field (M-H) shown by BFO, an obvious M-H loop was observed in BRFO compounds which could be due to the suppression of space modulated spin structure and was explained on the basis of weak ferromagnetism and field induced spin reorientation. UV-Vis spectroscopy evidenced a change in local FeO 6 environment due to shift in the 6 A 1g → 4 T 2g energy transition band. BRFO compounds with improved remnant magnetization and coercive field are applicable for magnetoelectric devices.

Temperature Dependent Magnetic, Dielectric Studies of Sm-Substituted Bulk BiFeO3

Journal of Superconductivity and Novel Magnetism, 2011

Bismuth ferrite-(BiFeO 3) ceramic is the most studied and attractive multiferroic material with low magnetization, moderate leakage current, and low polarization. Samarium substituted bulk BiFeO 3 prepared at low synthesis temperature ∼600°C by the sol-gel process. Room temperature X-ray diffraction (XRD) patterns confirmed the formation of perovskite structure Bi 0.9 Sm 0.10 FeO 3 (BSFO) phases. Present compositions possess high dielectric constant (ε ≈ 199) and low dielectric loss (tan δ ≈ 0.009) at room temperature for 100 Hz frequency. Room temperature dielectric permittivity and dielectric loss decreased with increasing frequency from 100 Hz to 10 MHz. As the temperature increased, an enormous increase in both dielectric permittivity and dielectric loss is observed at all frequency regions. Temperature dependent M-H hysteresis loops were saturated. Spin glass-like ferromagnetic behavior is retained in M-H hysteresis loops measured from the low temperature region and normal ferromagnetic behavior is observed in the high temperature region, both at room temperature and above ∼ 350 K, 400 K, respectively. The origin of the ferromagnetic property in BSFO may be due to the presence of rare earth metal ions at the lattice sites of BFO.

Structural, Dielectric, Ferroelectric and Magnetic Properties of Bi0.80A0.20FeO3 (A=Pr,Y) Multiferroics

Journal of Superconductivity and Novel Magnetism, 2012

Gadolinium doped BiFeO 3 samples were successfully synthesized by sol-gel method. The X-ray diffraction patterns show the effect of Gd doping in bismuth ferrite on structural changes as well as reduction of impurity phases. Microstructural analysis explores the morphology of pure and Gd doped BiFeO 3. M-H plot for doped BFO shows that magnetization reach the value 0.20emu/g.Theferroelectricpolarizationforappliedelectricfieldapproaches0.20 emu/g. The ferroelectric polarization for applied electric field approaches 0.20emu/g.Theferroelectricpolarizationforappliedelectricfieldapproaches0.35 lC/cm 2 for Bi 0.85 Gd 0.15 FeO 3. The dielectric data also justified that there is the improvement of dielectric properties of BiFeO 3 on doping with Gd.

Structural, non-volatile magnetization, and dielectric studies on zinc-doped BiFeO3

Journal of Physics: Conference Series

We investigate the structure, non-volatile magnetization, and dielectric properties of zinc doped bismuth ferrite (Bi 1-z Zn z FeO 3 ; z = 0, 0.05, and 0.15) powder synthesized via sol-gel auto-combustion method. We have found that the doping of Zn induced the presence of Bi 25 FeO 40 as a secondary phase and decreased the lattice parameter of bismuth ferrite (BFO) phase structure. Furthermore, the doping decreases the dielectric constant and increases the slope of magnetization and magnetic coercivity. The increase of magnetic coercivity value implies the increase of non-volatile magnetization properties.