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S. K. Sourav,S. K. Parida,R. N. P. Choudhary,Umakant Prasad 한국전기전자재료학회 2023 Transactions on Electrical and Electronic Material Vol.24 No.5
This communication describes a solid-state reaction prepared bismuth oxide and related complex compounds (BNKMT) of a chemical composition (1-x)BiFeO3-x(Bi0.5 Na0.25 K0.25 Ti0.5 Mn0.5 O3), where x = 0.15 and 0.20. Structural studies of the complex system show rhombohedral crystal symmetry (#R3c). The homogeneous distribution of the grains and grain boundaries throughout the sample surface clearly defined grain boundaries, which play a significant part in the conductivity mechanism, as revealed by the analysis of scanning electron microscopy micrographs and electrical properties. An energydispersive X-ray analysis spectrum was used to verify the processed materials’ purity and composition. According to the analysis of the FTIR-ATR spectrum, the prepared samples show stretching bands that correspond to their constituent elements. A dielectric investigation confirmed that the Maxwell–Wanger type of dielectric dispersion is present in the samples. Studies of impedance parameters as a function of temperature and frequency result in a negative temperature coefficient of resistance behavior. While ac conductivity research supports the presence of a thermally activated relaxation process in the materials. Analysis of electric modulus discloses a non-Debye type relaxation mechanism in the studied sample. Because the samples are semiconducting at high temperatures, semi-circular arcs have been seen in both the Nyquist and Cole–Cole plots. When compared to BNKTM 15%, BNKTM 20% has a bandgap energy of 5.9 eV, according to the analysis of UV visible spectra.
S. Kalingani,Satyaprakash Narayan Das,S. K. Pradhan,S. Bhuyan,R. N. P. Choudhary 한국전기전자재료학회 2023 Transactions on Electrical and Electronic Material Vol.24 No.1
In this present study the (Pb 1/2 Ba 1/2 )(Ni 1/2 W 1/2 )O 3 , [PBNW] perovskite compound has been formulated and synthesized by adopting a solid-state reaction technique. The detailed structural, morphological, and electrical characterization has been carried out to explore its characteristics for further application in the field of electronic devices and sensors. With the help of x-ray diff raction analysis orthorhombic structure has been recognized. Dielectric, impedance spectroscopy, and a.c. conductivity analysis has been carried out through a wide range of temperatures as well as frequency (temperature range 25–500 °C, frequency range 1 kHz to 1 MHz). Presence of a single semi-circular arc from Nyquist analysis points toward the grain contribution of the sample. An equivalent circuit model has been developed to explore its electrical behavior. The activation energy, as well as the charge carrier mobility, has been estimated. Methodical studies for dielectric properties at high temperatures are accomplished for analysing electrical inhomogeneity allied with surfaces, grain boundaries, or grains, which are imperative for fundamental characterization and device fabrication.
S. K. Pradhan,S. N. Das,S. Bhuyan,Seshadev Sahoo,R. N. P. Choudhary 한국전기전자재료학회 2020 Transactions on Electrical and Electronic Material Vol.21 No.2
Multiferroic gadolinium (Gd) doped BiFeO 3 (BFO) and PbTiO 3 (PT) samples [(Pb 1−x Bi 0.5x Gd 0.5x )(Fe x Ti 1−x )O 3 ] with x = 0.1, 0.3, 0.5 and 0.7 are formulated by adopting the solid state reaction process. The impact of gadolinium substitution in the crystal structure, morphological behavior and electrical properties has been studied. By altering the Gd concentration in the solid solution a change in the structure is observed that is from tetragonal to rhombohedral. The size of the grain in the compounds reduces as a result of enrich in gadolinium content of the furnished sample. The subsidence of lead minimizes the toxic behavior of the material with significant improvements in dielectric response of gadolinium modifi ed BiFeO3 – PbTiO 3synthesized system. From the impedance study, the material presents negative temperature coefficient of resistance characteristics and the impedance is due to the presence of grain and grain boundary eff ect inside the materials. It is realized that the remnant polarization decreases and frequency dependent ac conductivity increases with the concentration of gadolinium in the electronic system. From conductivity study, the equipped electronic materials show non-exponential type of conductivity relaxation.
Mishra S.,Choudhary R. N. P.,Parida S. K. 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.2
In this article, the influence of co-substitution of alkali and transition metals at the Ba/Mo site of host BaMoO4 (inorganic Scheelite) is reported. A new lead-free double perovskite BaLiFeMoO6 (BLFMO) is synthesized using a conventional solid-state reaction route, having tetragonal crystal symmetry with an average crystallite size of 93.2 nm and strain of 0.115%. Grains are grown by sintering and distributed uniformly through well-defined grain boundaries as obtained from scanning electron microscopy (SEM). The purity and compositional analysis through energy-dispersive analysis X-ray spectroscopy (EDX) technique confirms the presence of constituent elements Ba, Li, Fe, Mo, and O. Raman study supports the substitution of Li/Fe atoms at Ba and Mo sites in the host matrix. Direct bandgap energy of 2.99 eV is calibrated using the ultraviolet–visible (UV–Vis) spectrum; may be suitable for photovoltaic applications. Maxwell–Wagner dielectric response, non-Debye relaxation, activation energy, and negative temperature coefficient resistance (NTCR) behavior are the outcomes of the synthesized sample characterized using dielectric, impedance, modulus, and conductivity plots in a wider spectrum of frequency (1 kHz–1 MHz) and temperatures (25–500 °C). The contribution of both grains and grain boundaries in the conduction mechanism has been investigated using Nyquist's fitting data calibrated from ZSIMPWIN software. A decrease in the magnitude of grain boundary resistance with a rise in temperature in fitted Nyquist's plot suggests the presence of semiconducting nature in the material. Analysis of leakage current density suggests that the nature of the conduction mechanism follows to the space charge limited current process. The study of temperature-dependent resistance supports BLFMO as a good candidate for NTC thermistor-related device applications. The study of polarization–electric field hysteresis loop suggests the possibility of the ferroelectric nature in the studied sample.
Sourav S. K.,Parida S. K.,Choudhary R. N. P.,Prasad Umakant 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.4
In this communication, the synthesis (solid-state reaction) and characterization (XRD, SEM, EDX, and IS) of the (1 − x) BiFeO3 − x(BiNaKTiMnO 3), (x = 0.05 and 0.1) ceramics were reported. The structural analysis suggests a rhombohedral crystal symmetry (#R3c) with an average crystallite size of 39.6 nm and micro-lattice strain of 0.000401 in x = 0.05 sample, whereas average crystallite size of 46.6 nm and lattice strain of 0.00133 in x = 0.1 sample, respectively. The growth and distribution of the grains and the position of grain boundaries were studied from a scanning electron microscope (SEM). The purity and compositional analysis of the prepared samples were checked from an energy-dispersive X-ray analysis (EDX) image. The study of the Fourier-transform infrared spectroscopy (FTIR) spectrum suggests the presence of a stretching band of the constituent elements in the modifi ed bismuth ferrite. The presence of the Maxwell–Wanger type of dispersion was confirmed by a dielectric study. The investigation of impedance as a function of temperature and frequency reveals the existence of a negative temperature coefficient of resistance (NTCR). A non-Debye kind of relaxation mechanism is revealed by electric modulus analysis; however, a thermally induced relaxation process is confi rmed by an ac conductivity study. The semi-circular arcs in the Nyquist and Cole–Cole plots indicate that the sample is semiconducting. BNKTM 5% has an energy bandgap of 2.9 eV, while BNKTM 10% has an energy bandgap of 2.7 eV, according to UV–visible spectra. The field-dependent hysteresis loop is analogous to the onset of ferroelectricity.
( Shanti Choudhary ),( Wenli Li ),( Derek Bickhart ),( Ramneek Verma ),( R. S. Sethi ),( C. S. Mukhopadhyay ),( Ratan K. Choudhary ) 한국축산학회(구 한국동물자원과학회) 2018 한국축산학회지 Vol.60 No.7
Background: Xanthosine treatment has been previously reported to increase mammary stem cell population and milk production in cattle and goats. However, the underlying molecular mechanisms associated with the increase in stem cell population and milk production remain unclear. Methods: Primiparous Beetal goats were assigned to the study. Five days post-partum, one mammary gland of each goat was infused with xanthosine (TRT) twice daily (2×) for 3 days consecutively, and the other gland served as a control (CON). Milk samples from the TRT and CON glands were collected on the 10th day after the last xanthosine infusion and the total RNA was isolated from milk fat globules (MEGs). Total RNA in MFGs was mainly derived from the milk epithelial cells (MECs) as evidenced by expression of milk synthesis genes. Significant differentially expressed genes (DEGs) were subjected to Gene Ontology (GO) terms using PANTHER and gene networks were generated using STRING db. Results: Preliminary analysis indicated that each individual goat responded to xanthosine treatment differently, with this trend being correlated with specific DEGs within the same animal’s mammary gland. Several pathways are impacted by these DEGs, including cell communication, cell proliferation and anti-microbials. Conclusions: This study provides valuable insights into transcriptomic changes in milk producing epithelial cells in response to xanthosine treatment. Further characterization of DEGs identified in this study is likely to delineate the molecular mechanisms of increased milk production and stem or progenitor cell population by the xanthosine treatment.