D. Das

Bio: D. Das is an academic researcher. The author has contributed to research in topics: Coercivity & Magnetocapacitance. The author has an hindex of 1, co-authored 4 publications receiving 3 citations.

Dielectric and magnetodielectric properties of Bi0.95Tb0.05Fe0.95Co0.05O3 nanoparticles

Abstract: Bi095Tb005Fe095Co005O3 (BTFCO) nanoparticles (NPs) have been prepared using a chemical sol-gel method and characterized by x-ray diffraction (XRD), dielectric and magnetodielectric measurements XRD pattern of the prepared sample shows all crystal planes of BiFeO3 (BFO) confirming successful preparation of the desired NPs Frequency dependent dielectric constant (er) curves exhibit an enhancement of cr in the BTFCO NPs in comparison with the pristine BFO sample Frequency dependent imaginary part of electric modulus curves exhibit a peak denoting presence of a relaxation process and activation energy obtained from Arrhenious fitting is found to be 034 eV Variation of magnetocapacitance in presence of magnetic field is stronger in BTFCO in comparison with the pristine BFO and it is a signature of increased magnetoelectric effect in the doped BFO

Improvement of magnetic and ferroelectric properties of BiFeO3 nanoparticles on Tb and Co substitution

Abstract: Tb and Co substituted bismuth ferrite nanoparticles (NPs) with chemical composition Bi1-xTbxFe1-yCoyO3 (x = 0, 0.05; y = 0, 0.05) have been synthesized by a sol-gel method and characterized by x-ray diffraction (XRD), Mossbauer spectroscopy, dc magnetization and electric polarization measurements. The aim of the present work is to improve ferroelectric properties of BiFeO3 by substitution of Tb3+ ions in Bi3+ site and magnetic properties by substitution of Co2+ in Fe3+ site. The XRD patterns of all prepared samples show formation of the desired phase along with a small amount of impurity. Room temperature Mossbauer spectroscopic studies reveal that all samples are in magnetically ordered state. Magnetic hysteresis loops of all samples indicate a significant enhancement of magnetic moment and coercivity whereas electric polarization measurements at room temperature reveal an improvement of ferroelectric properties in the co-substituted sample.

Magnetoelectric and hyperfine properties of x(CoFe2O4)-(1-x)(BiFeO3) (x=0.2-0.4) nanocomposites

Abstract: Nanocomposites of nominal composition x(CoFe2O4)-(1-x)(BiFeO3) (x=0.2, 0.3 and 0.4) have been prepared by using the sol-gel method. XRD patterns of the samples annealed at 600 °C confirm formation of BiFeO3-CoFe2O4 nanocomposites with presence of both perovskite BiFeO3 (BFO) and spinel CoFe2O4 (CFO). All possible crystallographically inequivalent sites of BFO and CFO have been confirmed by 57Fe Mossbauer spectroscopy. A substantial increment of magnetocapacitance has been observed in the nanocomposites (NCs) with respect to the pristine BFO confirming stronger magnetoelectric coupling in BFO on formation of the NC.

Complex magnetic properties of TbMn1-xFexO3 (x = 0.1 and 0.2) nanoparticles prepared by the sol-gel method

Abstract: TbMn1-xFexO3 nanoparticles (NPs) with x = 0, 0.1 and 0.2 have been prepared by adopting the chemical sol-gel method. Phase identification and particle size estimation are done by XRD analysis. M-H measurements at 5 K indicate a complete ferromagnetic behaviour in the Fe-doped samples with large coercivity whereas the pristine sample shows presence of both ferromagnetic and antiferromagnetic orders. ZFC and FC magnetization curves of all samples show signature of antiferromagnetic ordering of both terbium and manganese magnetic moments along with a systematic shift of ordering temperatures with Fe substitution. 57Fe Mossbauer spectroscopic measurements of the Fe-doped samples at room temperature confirm the paramagnetic behaviour and reduction of electric field gradient around Fe probe atoms with increase of Fe concentration.

Mossbauer studies of BiFeO 3 Mulitiferroic nanoparticles doped with Eu

Abstract: This work presents the results of BiFeO3 and Bi0.9Eu0.1FeO3 multiferroic materials, synthesized via a simple solid-phase reaction method. Both of the synthesized materials were in the rhombohedral R3c structure as observed by X-ray diffraction (XRD). The presence of a doublet along with a sextet in Mossbauer spectra indicates an impurity phase (Bi2Fe4O9). The presence of Fe2+ ions are confirmed from Mossbauer spectroscopy study in the Bi0.9Eu0.1FeO3 sample. And the Bi0.9Eu0.1FeO3 exhibited a slight lattice distortion, observable from the results of XRD and Mossbauer spectra. We can conclude that growing of crystal homogeneity of Bi0.9Eu0.1FeO3 is better than BiFeO3.

Effect of zinc doping on structural, magnetic and dielectric properties of perovskite (Tb 0.874 Mn 0.106 )MnO 3−δ

Abstract: The solid solutions (Tb0.874Mn0.106)Mn1−xZnxO3−δ (0.0 ≤ x ≤ 0.20) have been synthesized by the conventional solid state reaction. The effect of Zn doping on structural, magnetic, and dielectric properties of (Tb0.874Mn0.106)Mn1−xZnxO3−δ (0.0 ≤ x ≤ 0.20) has been discussed. All samples in the series crystallize in Pnma space group at room temperature confirmed by powder X-ray, neutron, and selected area electron diffraction data. Two magnetic orderings are found at 42 and 32 K for the x = 0.0 to 30 and 16 K for x = 0.20, respectively. The magnetic hysteresis loops showed that a transition occurs from metamagnetic to normal canted antiferromagnetic at lower temperatures. Dielectric constant anomaly was not found below 300 K.