Bharat Kataria

Size-controlled electrical properties of sol–gel-grown nanostructured Gd0.95Ca0.05MnO3

In this communication, we report the results of the studies on electrical properties of cost-effective modified sol–gel-grown nanostructured Gd0.95Ca0.05MnO3 (GCMO) manganites sintered at different temperatures. Structural investigations, carried out using X-ray diffraction measurements, reveal the single-phasic nature of GCMO samples having orthorhombic unit cell structure. Frequency-dependent variation in AC conductivity (σAC) has been discussed on the basis of correlated barrier hopping (CBH) mechanism for the GCMO samples sintered at lower temperatures. Sintering temperature-induced transition from CBH mechanism to Maxwell–Wagner relaxation processes has been discussed in detail. Size-induced modifications in the impedance response of the samples have been understood, in detail, using size effects and Cole–Cole plots.Graphical Abstract

Structure-property correlations in monovalent mixed oxide La1−xKxMnO3(0.0≤x≤0.3)manganites

Substitution of monovalent K+ at La3+ in solid state reaction synthesized La1−xKxMnO3(0.0≤x≤0.3) manganites results in metallic behavior. Increase in K+ content (x ≤ 0.15) enhances the FM interactions through ZDE mechanism while for higher x > 0.15, structural disorder and AFM interactions between Mn4+ ions become prominent.

Investigations of magnetoelectric behavior in BiFe0.95Co0.05O3 nanoparticles

Nanophasic BiFe0.95Co0.05O3 (BFCO) particles were synthesized using low cost, easy, simple, environment friendly and low temperature acetate precursor based modified sol–gel method. Influence of particle size and magnetic field on the structural, dielectric, impedance and a.c. conductivity of BFCO is investigated. X-ray diffraction (XRD) measurement has been performed to understand the structural modifications in the samples upon increasing the sintering temperature. Crystallite size (CS) increases from 33.62nm to 39.56nm due to agglomeration effect between the smaller crystallites. Effect of sintering temperature on the dielectric, impedance and conductivity has been studied and understood in the context of the creation of crystallite (particle) size and oxygen vacancies created due to high temperature sintering process. Magnetic field induced modifications in all these electrical properties [magnetoelectric (ME) effects] for the presently studied BFCO samples have been discussed on the basis of magnetos...

Grain boundary effects on the structural, microstructural and transport behavior of sol – gel grown PrMnO3 nanoparticles

In this communication, we report the results of the studies on the grain boundary (GB) effect on the structural, microstructural and transport properties of nanostructured PrMnO3 (PMO) manganites synthesized by acetate precursor based sol – gel method. As synthesized PMO samples were sintered at various temperatures to understand the role of sintering temperature in modifying the structure – property correlations in the context of GB effects. Structural analysis using X-ray diffraction studies reveal the single phasic nature of all the PMO samples while TEM analysis reveals uniform particle size distribution with agglomeration effect observed in samples sintered at higher temperatures. SEM micrographs depict the increase in grain size with sharp grain boundaries in the samples sintered at a higher temperature. Size-dependent resistivity behavior of the PMO samples have been understood in the light of grain size modification and GB effect.

Temperature Dependent Switching of Magnetoresistance in Trilayered ZnO/La0.7Sr0.3MnO3/SrNb0.2Ti0.8O3 Device

We report the I–V characteristics and the magnetoresistance (MR) behavior of trilayered ZnO (n) (50 nm) / La0.7Sr0.3MnO3 (LSMO) (p) (100 nm) / SrNb0.2Ti0.8O3 (SNTO) (n) manganite based thin film device grown using Pulsed Laser Deposition (PLD) technique. The LSMO/SNTO and ZnO/LSMO junction diodes exhibit good rectifying behavior in the temperature range 5–300 K. The observed decrease in the values of saturation voltage (VC) with increase in temperature has been explained on the basis of band structure of the p‐type LSMO manganite. In addition, with increase in applied field up to 8 T, VC increases at T> 120 K for LSMO/SNTO and at T> 150 K for ZnO/LSMO resulting into positive MR at higher temperatures. The temperature and field dependent variation in MR has been discussed in the context of field induced modification in the band gap, presence of different electronic phases in p‐type LSMO manganite at various temperatures.