Clastin Sathish - Academia.edu (original) (raw)

Papers by Clastin Sathish

Journal of Physics: Condensed Matter

We present measurements of resistivity, x-ray absorption (XAS) and emission (XES) spectroscopy to... more We present measurements of resistivity, x-ray absorption (XAS) and emission (XES) spectroscopy together with ab initio band structure calculations for quasi two dimensional ruthenate Na2RuO3. Density function calculations (DFT) and XAS and XES spectra both show that Na2RuO3 is a semiconductor with an activation energy of ∼80 meV. Our DFT calculations reveal large magneto-elastic coupling in Na2RuO3 and predict that the ground state of Na2RuO3 should be antiferromagnetic zig-zag.

Bismuth oxy-sulfide Bi4O4S3, which was recently claimed to be an exotic superconductor (Tc = 4.5 ... more Bismuth oxy-sulfide Bi4O4S3, which was recently claimed to be an exotic superconductor (Tc = 4.5 K), was studied by magnetic susceptibility and electrical resistivity measurements. Single-phase Bi4O4S3 was successfully prepared by a high-pressure method, and its lattice parameters and normal-state resistivity, as well as the density of states at the Fermi level, were found to be comparable with those determined earlier. However, bulk superconductivity was absent (>2 K) in the compound, which contradicted the observations in ongoing experiments. The slight difference between the high-pressure phase and superconducting phase of Bi4O4S3 is expected to be a possible reason for this discrepancy. The results of the present study imply that if the high-pressure phase is not identical to the superconducting phase, the former can be a possible host material for the exotic layered Bi4O4S3 superconductor.

J Phys Soc Jpn, Jul 15, 2013

日本物理学会講演概要集, Mar 26, 2013

Journal of the Physical Society of Japan, Jul 1, 2013

Science of Advanced Materials, 2014

ABSTRACT The effect of Sn- or Zn-substitution on the temperature coefficient of electrical resist... more ABSTRACT The effect of Sn- or Zn-substitution on the temperature coefficient of electrical resistivity of antiperovskite Mn3AgN compound was evaluated based on electrical resistivity, magnetization, and specific heat measurements. The non-doped Mn3AgN compound exhibited a moderately low temperature coefficient of electrical resistivity (123 ppm/K) at temperatures above 277 K. By 40 atomic% doping with Sn, a remarkably low coefficient of 23 ppm/K was achieved. For the formulation Mn3Ag0.5Zn0.5N, Zn substitution produced a low coefficient of 35 ppm/K over a much wider temperature range than achieved with Sn for temperatures above 227 K. Although the origin of the observed unusual temperature dependence of the electrical resistivity seemed complicated, the data indicated that substitution of Ag in Mn3AgN is a promising means of developing materials with an excellent low temperature coefficient of electrical resistivity for practical applications.

ChemInform

Sr2MO2Cl2 (M: Mn, Ni) and Ba2PdO2Cl2 are prepared under high-pressure high-temperature conditions... more Sr2MO2Cl2 (M: Mn, Ni) and Ba2PdO2Cl2 are prepared under high-pressure high-temperature conditions using stoichiometric amounts of SrO2, MnCl2, SrCl2, BaO, PdO, and BaCl2 (Pt capsule, 3 GPa, 1400 °C, 1 h; resp.

Optik - International Journal for Light and Electron Optics, 2015

Optically good quality organic crystals of urea phthalic acid (UPA) were grown successfully by sl... more Optically good quality organic crystals of urea phthalic acid (UPA) were grown successfully by slow evaporation solution growth technique at room temperature. The crystalline nature of the crystal was assessed by powder XRD analysis. The presence of various functional groups has been identified by using FT-IR spectral analysis. UV-vis spectra show good transparency in the entire visible region. Dielectric constant and dielectric loss were measured for the grown crystals. Photoconductivity studies were also taken for the grown crystals. Mechanical studies of the crystals were studied using Vickers microhardness tester.

Journal of Solid State Chemistry, 2014

Advances in Condensed Matter Physics, 2013

e physical properties of polycrystalline Mn 3 SbN were investigated using measurements of the ma... more e physical properties of polycrystalline Mn 3 SbN were investigated using measurements of the magnetic, calorimetric, and electronic transport properties. At room temperature, the phase crystallizes in a tetragonal structure with symmetry. A remarkably sharp peak in the heat capacity versus temperature curve was found near 353 K. e peak reaches 723 J mol −1 K −1 at its highest, which corresponds to a transition entropy of 10.2 J mol −1 K −1 . e majority of the large entropy change appears to be due to lattice distortion from the high-temperature cubic structure to the room-temperature tetragonal structure and the accompanying Ferrimagnetic transition.

Proceedings of the 12th Asia Pacific Physics Conference (APPC12), 2014

Applied Physics A, 2015

Novel semi-organic single crystals of bis (potassium) 2,4-dinitrophenolate monohydrate were grown... more Novel semi-organic single crystals of bis (potassium) 2,4-dinitrophenolate monohydrate were grown by slow evaporation technique at room temperature. Single-crystal XRD confirms that the crystal belongs to monoclinic system with space group C2/c. 1 H NMR and 13 C NMR studies were conducted for the crystal. In order to know the purity, LC-MS studies were also conducted for the crystal. Functional groups present in the synthesized compound were confirmed by FT-IR analysis. UV-Vis studies show that the crystal has a lower cutoff wave length at 461 nm. Dielectric studies were carried out to study the charge transport mechanism in the crystal. Photoconductivity study exhibits the positive photoconductivity nature of the grown crystal. Nonlinear absorption coefficient (b), nonlinear refraction (n 2 ), and third-order susceptibility (v (3) ) were also evaluated for the grown crystal.

Solid State Communications, 2012

In this study, we address the superconductivity of the Zn-and Mn-doped Fe-based superconductors B... more In this study, we address the superconductivity of the Zn-and Mn-doped Fe-based superconductors Ba(Fe 1−x−y M x Co y ) 2 As 2 (M = Zn and Mn) and Sr(Fe 0.9−x Zn x Co 0.1 ) 2 As 2 . The impurity is successfully doped into the lattice of the superconductors under a high-pressure heating condition, resulting in a continuous decrease in T c toward zero. Not only the optimally doped, but also the under-and over-doped superconducting states show a noticeable decrease in T c as a function of the Zn concentration. The rate of decrease, however, is not as large as the theoretical value expected from the s ± -wave model, suggesting that this model is unlikely to be applied to the superconductivity of the present 122 system.

Solid State Communications, 2014

Superconducting cubic δ-MoC 0.75 has been synthesized by a high-pressure synthesis method at a pr... more Superconducting cubic δ-MoC 0.75 has been synthesized by a high-pressure synthesis method at a pressure of 17 GPa in a Kawai-type instrument, followed by studies on the crystal structure by synchrotron X-ray diffraction. Electromagnetic measurements indicated a superconducting transition temperature T c of 14.3 K, which is the highest T c value experimentally confirmed among the binary metal carbides. The cubic δ-MoC 0.75 prepared in this study could be considered as a weakly coupled superconductor.

Journal of the Physical Society of Japan, 2013

Bismuth oxysulfide Bi 4 O 4 S 3 , which has recently been claimed to be an exotic superconductor ... more Bismuth oxysulfide Bi 4 O 4 S 3 , which has recently been claimed to be an exotic superconductor (T c ¼ 4:5 K), was investigated by magnetic susceptibility and electrical resistivity measurements as well as by electron probe microanalysis. Single-phase Bi 4 O 4 S 3 was successfully prepared by a high-pressure method, and its lattice parameters and normal-state resistivity, as well as the density of states at the Fermi level, were found to be comparable to those determined earlier. However, the observed superconductivity was most likely impurity-driven, strictly contradictory to the observations in ongoing experiments. The present results indicate that the superconductivity of Bi 4 O 4 S 3 does not truly reflect the bulk nature of the BiS 2 layered phase, regardless of the manner in which Bi 4 O 4 S 3 is synthesized. We discuss possible superconducting impurities.

Journal of the American Chemical Society, 2014

5d and 3d hybrid solid-state oxide Ca 2 FeOsO 6 crystallizes into an ordered double-perovskite st... more 5d and 3d hybrid solid-state oxide Ca 2 FeOsO 6 crystallizes into an ordered double-perovskite structure with a space group of P2 1 /n with high-pressures and temperatures. Ca 2 FeOsO 6 presents a long-range ferrimagnetic transition at a temperature of ∼320 K (T c ) and is not a band insulator, but is electrically insulating like the recently discovered Sr 2 CrOsO 6 (T c ∼725 K). The electronic stat of Ca 2 FeOsO 6 is adjacent to a half-metallic state as well as that of Sr 2 CrOsO 6 . In addition, the high-T c ferrimagnetism was driven by lattice distortion, which was observed for the first time among double-perovskite oxides and represents complex interplays between spins and orbitals. Unlike conventional ferrite and garnet, the interplays likely play a pivotal role of the ferrimagnetism. A new class of 5d−3d hybrid ferrimagnetic insulators with high-T c is established to develop practically and scientifically useful spintronic materials.

Journal of Solid State Chemistry, 2013

Single crystals of the osmium-containing compound Ca 3 OsO 6 have been successfully grown under h... more Single crystals of the osmium-containing compound Ca 3 OsO 6 have been successfully grown under high-pressure conditions, for the first time. The crystal structure of Ca 3 OsO 6 were characterized as an ordered double-perovskite structure of space group P2 1 /n with the Ca and Os atoms being fully ordered at the perovskite B-site. The electromagnetic analysis shows that the crystal exhibits a semiconductorlike behavior below 300 K and undergoes an antiferromagnetic transition at 50 K.