23 Result(s)

Article

Electrical transport in La_1−x Ca _x MnO₃ thin films at low temperatures

We report here the low-temperature resistivity of the chemical solution deposited La_1−x Ca _x MnO₃ (x=0.2, 0.3 and 0.33) thin films on LaAlO₃ substrates. The films...

S Angappane, K Sethupathi, G Rangarajan in Pramana (2002)

Article

Polarized Raman scattering in single crystals of Nd_0.7Sr_0.3MnO₃

We report polarized Raman scattering in single crystals of Nd_0.7Sr_0.3MnO₃. The temperature dependence of the MnO₆ octahedral bending and stretching modes observed in the XX spectra points to the existence of loca...

M Pattabiraman, G Rangarajan, Kwang-Yong Choi, P Lemmens, G Guentherodt… in Pramana (2002)

Chapter

Orbital Order and Orbital Fluctuations in Colossal Magnetoresistive Manganites. An Investigation with ⁵⁵Mn and ¹³⁹La NMR

⁵⁵Mn and ¹³⁹La NMR techniques are shown to be an excellent tool for detecting changes in the local electronic properties of colossal magnetoresistance manganites. Based on this we discuss the pos...

G. Papavassiliou, M. Belesi, M. Fardis… in Magnetic Resonance in Colloid and Interfac… (2002)

Article

Annealing effect on transport properties of Nd_0.67Sr_0.33MnO₃ thin films

Annealing dependence of the lattice parameter, resistivity, magnetoresistance and thermopower have been studied on Nd_0.7-Sr_0.33MnO₃ thin films deposited on LaAlO₃ and alumina substrates by pulsed laser ablation. ...

M Pattabiraman, P Murugaraj, G Rangarajan, V Prasad, S V Subramanyam, V S Sastry… in Pramana (2000)

Article

Dispersion-induced insulator-to-metal transition in polyaniline

Melt dispersion processing--without solvents or “secondary dopants”--pushes polyaniline reproducibly to the metallic side of the IM transition, although the undispersed polyaniline is on the insulator side. Th...

B. Wessling, D. Srinivasan, G. Rangarajan, T. Mietzner… in The European Physical Journal E (2000)

Article

DC electrical conduction in heat-treated poly nickel phthalocyanine

Heat treatment of poly nickel phthalocyanine leads to a charge transfer and hence there is an improvement in conductivity by 5 orders of magnitude. DC electrical conductivity measurements have been carried out...

B Sanjai, Anasuya Raghunathan, T S Natarajan, G Rangarajan… in Bulletin of Materials Science (1997)

Article

Structural and superconducting properties of melt-grown Y–Ba–Cu–O superconductors

YBa₂Cu₃O₇ (123) samples with varying Y₂BaCuO₅ (211) concentrations (0 mol %, 20 mol %, 28 mol %, and 50 mol %) were synthesized by the melt-growth process. Microstructural characterizations were done using x-ray ...

R. Gopalan, T. Rajasekharan, T. Roy, G. Rangarajan… in Journal of Materials Research (1996)

Article

Microstructural investigations on melt grown RE-Ba-Cu-O (RE = Y, Gd and Nd) systems

A melt growth process has been carried out on RE-Ba-Cu-O (RE = Y, Gd and Nd) superconductors in order to fabricate grain oriented samples that support a high critical current density (J _c). Preliminary results on...

R. Gopalan, T. Rajasekharan, T. Roy, G. Rangarajan in Journal of Materials Science (1996)

Article

Specific heat of single crystalline PrBa₂Cu₃O_7−δ in magnetic fields

Low temperature specific heat studies on contamination free single crystals of PrBa₂Cu₃O_7−δ (PBCO) are reported in the temperature range 1.6–40K and in applied magnetic fields ofH=0T, 2T, 5T and 7.5T. The measure...

S. Uma, W. Schnelle, E. Gmelin, G. Rangarajan, A. Erb… in Czechoslovak Journal of Physics (1996)

Article

Electrical conductivity and magneto-resistance studies on polyaniline-PMMA blends at very low temperature

D.C. electrical conductivity of polyaniline(33%,40%) blended with PMMA was measured from 5K to 300mK. The conductivity behaviour is consistent with fluctuation induced tunneling. Magneto-resistance (MR) was me...

D. Srinivasan, Anasuya Raghunathan, T. S. Natarajan… in Czechoslovak Journal of Physics (1996)

Article

Magnetization and critical state models in YNi₂B₂C

Magnetization measurements have been performed on superconducting YNi₂B₂C at different temperatures below T_c with maximum applied fields ranging from 200 Oe to 15 kOe. The experimental data were analyzed using Ki...

Narayani Senthilkumaran, S. Ravi, G. Rangarajan… in Czechoslovak Journal of Physics (1996)

Article

Magnetic susceptibility and specific heat of Pr_2−xCe_xCuO_4−y

We report here the measurements of magnetic susceptibility of Pr_2−xCe_xCuO_4−y (x=0, 0.05 and 0.15) from 2K to 300K and the specific heat of Pr_1.85Ce_0.15CuO₄ between 6K and 60K. Fitting of the magnetic susceptibili...

Nithya Ravindran, T. Sarkar, G. Rangarajan… in Journal of Superconductivity (1995)

Article

Pole figure studies in melt grown Y-Ba-Cu-O samples

R. Gopalan, A. K. Singh, T. Rajasekharan… in Journal of Materials Science Letters (1995)

Article

DC magnetization studies of (Pr _x Y_1−x )Ba₂Cu₃O_7−y

Magnetization was measured on Pr-doped YBa₂Cu₃O_7−y for fields up to 5·5T. The paramagnetic behaviour is correlated to the free ion values of Pr³⁺ and Pr⁴⁺. Hysteresis experiments were don...

L S Vaidhyanathan, C K Subramaniam, G Rangarajan in Bulletin of Materials Science (1991)

Article

Role of lead in the growth of the highT _c phase in the Bi_2−x Pb _x Sr₂Ca₂Cu₃O _y systems

Bi_2−x Pb _x Sr₂Ca₂Cu₃O _y superconducting samples with 0<x<0·3 have been synthesized and characterized using X-ray powder diffrac...

L S Vaidhyanathan, A M Niraimathi, P Majumdar… in Bulletin of Materials Science (1991)

Article

Oxygen-enrichment of YBa₂Cu₃ YBa₂Cu₃O_7-δ using the fluidization techniqueusing the fluidization technique

The oxygen-deficient phase of the highT _c superconductor, YBa₂Cu₃O₇, was oxygen-enriched using the fluidization technique to give good superconducting properties. The normal method of oxyg...

U V Varadaraju, G V Subba Rao, K D Chandrasekaran… in Bulletin of Materials Science (1989)

Article

Specific heat of YBa₂Cu₃O_7−x from 4.2 to 60 K

The specific heat of superconducting oxide compound, YBa₂Cu₃O_{7 −x} , is studied using a quasi-adiabatic calorimeter from 4.2 to 60 K. The analysis of the specific heat data below 15 K gives a value...

N Sankar, V Sankaranarayanan, R Srinivasan, G Rangarajan, G V Subba Rao in Pramana (1988)

Article

An experimental study of magnetic flux diffusion into superconducting tin and indium cylinders

Measurements have been made of the total time required for the penetration of magnetic flux into cylindrical specimens of pure indium and pure tin, both type I superconductors, when an overcritical axial magne...

K. Aswathy, G. Rangarajan, R. Srinivasan… in Journal of Low Temperature Physics (1986)

Article

Electron transport in Chevrel phase superconductors, Cu_1.8Mo₆S_8−y Se _y , 0⩽y⩽8 and Cu_1.8Mo₆S_8−y Te _y , 0⩽y⩽4—Fit to Cote-Meisel theory

Normal state electrical resistivity of the Chevrel phase compounds of the type Cu_1.8Mo₆S_8−y Se _y , 0⩽y⩽8 and Cu_1.8Mo₆S_8−y Te _{y ...}

V Sankaranarayanan, G Rangarajan, R Srinivasan in Pramana (1984)