M. Muneeswaran

Effect of Dy-substitution on the structural, vibrational, and multiferroic properties of BiFeO3 nanoparticles

Dysprosium (Dy) modified BiFeO3 [Bi1−xDyxFeO3 (x = 0.05, 0.10, and 0.15)] nanoparticles have been synthesized by a low temperature co-precipitation method. Rietveld analysis of X-ray diffraction data reveals a transformation from rhombohedral structure to orthorhombic structure with increase in the Dy concentration. From the transmission electron microscopy analysis, it is observed that the particle sizes of Bi1−xDyxFeO3 (x = 0.05, 0.10, and 0.15) nanoparticles range between 50–70, 40–50, and 30–50 nm, respectively. Raman spectra of Bi1−xDyxFeO3 (x = 0.05) belonging to rhombohedral (R3c) structure show 4A1 and 7E fundamental Raman modes in the range of 100–650 cm−1 and two-phonon scattering modes such as 2A4 (longitudinal optical), 2E8 (transverse optical (TO)), and 2E9 (TO) in the range of 950–1270 cm−1. Suppression, broadening, and shifting of Raman modes have been observed with further increase in Dy concentration. The fundamental Raman modes of Bi1−xDyxFeO3 (x = 0.15) are assigned under orthorhombic (...

Synthesis of nanosized BiFeO3 powders by co-precipitation method

A soft chemical co-precipitation method is proposed for the synthesis of nanosized multiferroic BiFeO3 (BFO) powders. Pure phase (BFO) powder was obtained by controlling the chemical co-precipitation process, pH level and calcination temperature. The evolutions of phase constitution and structural characteristics showed that the BFO powders had R3c crystal structure under optimised conditions. Crystallite sizes deduced from X-ray diffraction line width analysis were found to be within 27–31 nm. Fourier transform infrared spectra showed that strong band corresponds to the Fe–O stretching and O–Fe–O bending vibrations. Dielectric and leakage behaviours were also measured at room temperature.

Effect of synthesis conditions on the photocatalytic property of multiferroic BiFeO3 towards the degradation of phenol red

Multiferroic BiFeO3 has been synthesized through hydrothermal route under different reaction conditions. From the basic characterization such as of X-Ray diffraction analysis (XRD), the synthesized Nps were found to having rhombohedral structure with R3c space group. Photodegradation studies of toxic dye phenol red have been investigated under visible light irradiation. Vibrating sample magnetometer (VSM) analysis has been carried out to identify the magnetic properties and recycle ability photocatalysts.

Photocatalytic activity of BiFeO3 nanoparticles synthesized through hydrothermal method

Multiferroic BiFeO3 (BFO) nanoparticles (Nps) were synthesized using hydrothermal method. From the X-Ray diffraction analysis (XRD), the synthesized Nps were found to having rhombohedral structure with R3c space group confirmed by Rietveld analysis. Fourier transform infrared spectroscopy (FTIR) analysis was carried out to identify the chemical bonds present in the BFO Nps. Photocatalytic properties of synthesized Nps were studied for the degradation of Methylene Blue (MB) dye under visible light of 150W.

Multiferroism in hydrothermally prepared Ce:BaTiO3 nanoparticles

Hydrothermally synthesized bare and cerium (Ce) doped BaTiO3 nanoparticles show tetragonal phase. The decrease of crystallite size (85-32 nm) and tetragonality (1.0026-1.0016) is observed by the addition Ce. FESEM reveals the uniformly segregated spherical particles. The red shift in the absorption peak and the decreased optical bandgap (3.07-2.71 eV) are indentified with Ce concentration. Ferromagnetism is observed in Ce doped sample with Ms – 5.293×10−3 emu/g. Room temperature ferroelectric measurement indicates the maximum saturation polarization (2. 00 µC/cm2) for bare sample at the driven field 4 kV.

Structural, electrical and magnetic properties of multiferroic Bi1-xGdxFeO3 (x = 0.00 and 0.15)

A co-precipitation method has been adopted to synthesis Bi1-xGdxFeO3 (x = 0.00 and 0.15) nanoparticles. XRD studies confirms the phase formation and the crystallite size measured by using Debye-Scherrer relation reveals particle sizes of 72 and 36 nm for Bi1-xGdxFeO3 (x = 0.00) and Bi1-xGdxFeO3 (x=0.15) respectively. A distinct anomaly peak has been observed around 390°C in Bi1−xGdxFeO3 (x = 0.00) and 273°C in Bi1-xGdxFeO3 (x=0.15) from the temperature dependent dielectric studies attributed to the antiferromagnetic to paramagnetic phase transition. Bi1-xGdxFeO3 (x=0.15) shows better leakage current characteristics due to partial substitution of stable rare-earth Gd3+ ions for volatile Bi3+ ions leading to the reduction in oxygen vacancies. Further, Bi1-xGdxFeO3 (x = 0.00) shows lower remnant polarization value and a antiferromagnetic behavior. Whereas, Bi1-xGdxFeO3 (x=0.15) shows higher remnant polarization value and a weak ferromagnetic behavior.