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Tunnel spectroscopy into the YBa2Cu4O8 compound

Il Nuovo Cimento D 16:10-11 (1994) 1885-1888

Authors:

P Romano, R Di Leo, A Nigro, AM Cucolo, B Dabrowski, PG Radaelli

Abstract:

We have realized planar tunnel junctions using both Y123 and Y124 single crystals as base electrodes and Pb as counterelectrode. The crystals, with T c =90 K (Y123) and T c =80 K (Y124), have been chemically etched and natural barriers were formed by a short air exposure. We have compared the tunneling spectra obtained on both systems. The features at about卤18mV of the Y123 compound are still observed in the Y124, while the low-bias structures at 卤5 mV are not present in the tunneling characteristics of the Y124 system. Linearity of the background conductance is also observed, with less steep slopes in Y124 that might indicate a reduced interlayer coupling in this system. 漏 1994 Societ谩 Italiana di Fisica.

Tunneling spectroscopy into YBa2Cu4O8: Intralayer and interlayer analysis.

Phys Rev B Condens Matter 50:14 (1994) 10397-10400

Authors:

AM Cucolo, RD Leo, P Romano, B Dabrowski, DG Hinks, PG Radaelli

Structural effects of hydrostatic pressure in orthorhombic La2-xSrxCuO4.

Phys Rev B Condens Matter 50:5 (1994) 3221-3229

Authors:

H Takahashi, H Shaked, BA Hunter, PG Radaelli, RL Hitterman, DG Hinks, JD Jorgensen

Synthesis and properties of a cuprate superconductor containing double mercury-oxygen layers.

Science 265:5170 (1994) 380-383

Authors:

PG Radaelli, M Perroux, M Marezio, S de Brion, JL Tholence, Q Huang, A Santoro

Abstract:

A cuprate superconductor containing double mercury layers was synthesized with a high-pressure, high-temperature technique. The compound, with chemical formula Hg(2)Ba(2)-Y1-xCaxCu(2)O(8-delta), contains a double HgO layer with structure similar to that of rock salt. The prototype compound Hg(2)Ba(2)YCu(2)O(8-delta) is an insulator. Superconductivity is induced in the system by partially replacing yttrium with calcium.

Low-energy spin fluctuations in YBa2Cu3O6.1 and ErBa2Cu3O6+x A Cu (1) T1 NQR study

Physica C: Superconductivity and its applications 226:3-4 (1994) 301-310

Authors:

SG Jang, C Bucci, R De Renzi, G Guidi, M Varotto, C Segre, P Radaelli

Abstract:

63Cu(1) NQR signals and their relaxation have been measured in YBa2Cu3O6.1 and ErBa2Cu3O6+x at temperatures between 10 K and 300 K. In YBa2Cu3O6.1 a peak is observed in the spin-lattice relaxation, T1-1, around 140 K. An explanation in terms of doped-hole motion is presented and alternative O(4)-O(5) diffusion mechanisms are critically discussed. In ErBa2Cu3O6+x the low-temparature T1-1 is dominated by magnetic fluctuations of Er; quantitative agreement is found when the correct ground state and magnetic dynamic properties of the rare earth are taken into account. 漏 1994.