N.Y. Vasanthacharya

Elusive superconductivity in polycrystalline samples of layered lanthanum nickelates

La2-xNiO4, La2-xSrxNiO4 and related layered nickelates have been investigated for possible presence of superconductivity. While there is clear onset of diamagnetism around 20 K in many of these nickelates, we do not, however, find any anomaly in the electrical resistivity, magnetoresistance or thermopower around 20 K. High energy spectroscopic studies show Ni to be in the 2+ oxidation state accompanied by a substantial proportion of oxygen holes.

Critical current density measurements of YBa2Cu3O7−x thin films by non-resonant r.f. absorption method

A new, contact-less technique for the measurement of the critical current density J c using the non-resonant r.f. absorption phenomenon is proposed. J c in thin film samples of YBa 2 Cu 3 O 7-x prepared by pulsed laser deposition are measured by this technique as well as the transport current method. Satisfactory agreement is obtained between the results of the two techniques.

Superconductivity in Ba(Pb,Bi,Sb)O3, Ba(Pb,Bi,Te)O3 and (Ba,La) (Pb,Bi,Tl)O3 systems

Abstract It is possible to substitute Bi in the superconducting BaPb 0.75 Bi 0.25 O 3 by Sb or Te without destroying the superconductivity. With Sb, a continuous series of solid solutions BaPb 0.75 Bi 0.25−y Sb y O 3 (0 ⩽ y ⩽ 0.25) exists, while with Te, perovskite BaPb 0.75 Bi 0.25−y Te y O 3 exists only upto y = 0.15. With increasing substitution by Sb or Te, T c decreases continously in both the systems. Superconductivity with a maximum T c of 8K is found in Ba 0.9 La 0.1 Pb 0.9−y Bi y Tl 0.1 O 3 for y = 0.25.

Electrical transport in the perovskite solid solution LaNi1−xCoxO3

LaBa_2CuCo_2O_8

Low-temperature synthesis of bismuth cuprates

and

Evolution of magnetic order in the system LaNi1-xMnxO3 (x < 0.10)

LaBa_2Cu_2CoO_{7.4}

Synthesis, characterization, redox and photocatalytic properties of Ce1-xPdxVO4 (0 <= x <= 0.1)

possessing defect-perovskite structures related to

Rapid synthesis of room temperature ferromagnetic Ag-doped LaMnO3 perovskite phases by the solution combustion method

YBa_2Cu_3O_7

Synthesis, structure and oxygen-storage capacity of Pr1−xZrxO2−δ and Pr1−x−yPdyZrxO2−δ

(123) have been prepared. The cobalt in both the phases substitutes for the plane copper [Cu(2)] sites, preserving the Cu---O chains of the (123) structure. Accordingly, removal of oxygen from the new phases transforms the orthorhombic structure to the tetragonal structure of