Gagan Dixit

Looking for the possibility of multiferroism in NiGd0.04Fe1.96O4 nanoparticle system

This paper reports the study of structural, electrical, magnetic and optical properties of Gd-doped nickel ferrite nanoparticles in order to investigate the possibility of multiferroism. The NiGd0.04Fe1.96O4 nanoparticles were prepared by a chemical route and characterized by various techniques. Doping with Gd ions induces poor ferroelectricity in nickel ferrite. This may be attributed to the small distortion in the centrosymmetric fcc structure because of the presence of large Gd ions.

Swift heavy ion-induced effects in Ce-doped nickel ferrite nanoparticles

Swift heavy ions of various energies are being used for material modifications. The induced modifications depend on the kind of defects produced during interaction of ions with the target material. In the present work, irradiation of 200 MeV Ag beam-induced effects in NiFe2O4 and NiCe0.04Fe1.96O4 nanoparticles are studied at two different fluences, 2×1012 and 1×1013 ions/cm2. Nanoparticles of nickel ferrite and Ce-doped nickel ferrite were prepared by chemical route. X-ray diffraction pattern shows peaks corresponding to pure spinel structure in both the systems, NiFe2O4 and NiCe0.04Fe1.96O4. The pristine as well as irradiated nanoparticles were characterized by high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, electron paramagnetic resonance spectroscopy (EPR) and vibrating sample magnetometer (VSM). Raman spectra show bands corresponding to spinel structure. After irradiation, the position of the bands does not change significantly for both samples. The widths corresponding to the same band in both the systems show opposite trend with fluence. VSM results show that after irradiation, the magnetization decreases from 40 to 32 A m2/kg for NiFe2O4 and from 39 to 31 A m2/kg for NiCe0.04Fe1.96O4. EPR results show that after doping with Ce as well as irradiation, the EPR line width is reduced, making samples important for applications.

HRTEM and FTIR investigation of nanosized zinc ferrite irradiated with 100 MeV oxygen ions

Present work aims to investigate effect of 100 MeV oxygen ion irradiation on the vibrational modes of zinc ferrite nanoparticles. Nanosize zinc ferrite systems of different crystallite size ranging from 12-62 nm were irradiated at the fluence of 1×10(13) and 5×10(13) ions/cm(2). High resolution transmission electron micrograph study indicates the structural disorder induced by ion irradiation. Bands corresponding to various vibrational modes in Fourier transform infrared spectra exhibit changes and are affected by the crystallite size/microstructure of pristine samples. The irradiation induced changes are dominated for sample ZF1000.

Investigations of structural and transport properties of Ca doped yttrium manganites

ABSTRACT Presently, the effect of divalent Ca ions on the structural and transport properties of YMnO3 is studied. A series of (Y1-xCaxMnO3 x = 0.00, 0.03, 0.05, 0.1, 0.25) samples were synthesized by solid state reaction method. X-ray diffraction shows that pure YMnO3 have hexagonal while Ca doped compounds possess mixed (hexagonal and orthorhombic) phase for all concentrations of Ca. Ferroelectric behavior of all samples was also investigated by PE loop. Furthermore, dielectric constant is found to improve after Ca doping which is understood in terms of electronic phase separation that generally occurs in charge ordered manganites.

Structural and electrical studies of La2NiO4system

We report the structural and electrical characteristics of bulk La 2 NiO 4 compounds synthesized by conventional solid state reaction route. The X-ray diffraction (XRD) was carried out to study the structure of samples. Rietveld refinement of XRD data confirm that the samples are of single phase and have tetragonal unit cell with space group I4/ mmm . Temperature dependent electrical resistivity measurements were performed to study the transport behavior. Semiconducting behavior was observed in the temperature range of 85 to 300 K. It has been found that samples obey the Arrhenius relation which is generally followed by the typical semiconductors.

Structural and electrical studies of La[sub 2]NiO[sub 4] system

We report the structural and electrical characteristics of bulk La 2 NiO 4 compounds synthesized by conventional solid state reaction route. The X-ray diffraction (XRD) was carried out to study the structure of samples. Rietveld refinement of XRD data confirm that the samples are of single phase and have tetragonal unit cell with space group I4/ mmm . Temperature dependent electrical resistivity measurements were performed to study the transport behavior. Semiconducting behavior was observed in the temperature range of 85 to 300 K. It has been found that samples obey the Arrhenius relation which is generally followed by the typical semiconductors.

Structural and electrical studies of La2NiO4 system

We report the structural and electrical characteristics of bulk La 2 NiO 4 compounds synthesized by conventional solid state reaction route. The X-ray diffraction (XRD) was carried out to study the structure of samples. Rietveld refinement of XRD data confirm that the samples are of single phase and have tetragonal unit cell with space group I4/ mmm . Temperature dependent electrical resistivity measurements were performed to study the transport behavior. Semiconducting behavior was observed in the temperature range of 85 to 300 K. It has been found that samples obey the Arrhenius relation which is generally followed by the typical semiconductors.