Soto, F., Berger, H., Cabo, L., Carballeira, C., Mosqueira, J., Pavuna, D., ...
The fluctuation-diamagnetism (FD) above the superconducting transition was measured in 2H-NbSe2 single crystals. The moderate uniaxial anisotropy of this compound, and some experimental improvements,...
Soto, F., Berger, H., Cabo, L., Carballeira, C., Mosqueira, J., Pavuna, D., ...
Electric and magnetic characterization of NbSe2 single crystals is first presented in detail. Then, some preliminary measurements of the fluctuation-diamagnetism (FD) above the transition temperature...
Three-dimensional dispersion induced by extreme tensile strain in La2–xSrxCuO4 films (2006)
Cloetta, D., Arisoa, D., Cancellieri, C., Abrecht, M., Mitrovic, S., Pavuna, D.
The electronic band structure probed by angle-resolved photoemission spectroscopy on thin epitaxial La2–xSrxCuO4 films under extreme tensile strain shows anomalous features compatible with c-axis...
Experimental Electronic Structure and Interband Nesting in BaVS_3 (2005)
Mitrovic, S., Fazekas, P., Sondergaard, C., Ariosa, D., Barisic, N., Berger, H., ...
The correlated 3d sulphide BaVS_3 is a most interesting compound because of the apparent coexistence of one-dimensional and three-dimensional properties. Our experiments explain this puzzle and shed...
Abrecht, M., Ariosa, D., Cloetta, D., Vobornik, D., Margaritondo, G., Pavuna, D.
We have optimized laser ablation thin film deposition and transfer procedures within synchrotron vault, specifically to perform angle-integrated and angle-resolved photoemission spectroscopy (ARPES)...
Ocko, M, Zivkovic, I, Prester, M, Drobac, D, Ariosa, D, Berger, H, ...
We report on AC susceptibility, resistivity, thermopower and measurements of sintered magnetic superconductor RuSr2GdCu2O8. The anti ferromagnetic phase transition at 133 K is seen clearly in the AC...
Photoemission, correlation and superconductivity: New avenues (2003)
Abrecht, M., Ariosa, D., Cloetta, D., Pavuna, D., Perfetti, L., Grioni, M., ...
Abrecht, M., Ariosa, D., Cloetta, D., Mitrovic, S., Onellion, M., Xi, X. X., ...
Angle-resolved photoemission spectroscopy reveals very surprising strain-induced effects on the electronic band dispersion of epitaxial La2-xSrxCuO4-delta thin films. In strained films we measure a...
Unexpected electronic properties of strained La1.85Sr0.15CuO4 epitaxial films (2003)
Ariosa, D., Abrecht, M., Cloetta, D., Pavuna, D., Onellion, M., Margaritondo, G.
Surprising results on electronic properties of strained thin La1.85Sr0.15CuO4 epitaxial films are reported. We report on the very first angle resolved photoemission (ARPES) measurements of the...
Carrier relaxation time divergence in single and double layer cuprates (2003)
Schneider, ML, Rast, S, Onellion, M, Demsar, J, Taylor, AJ, Glinka, Y, ...
We report the transient optical pump-probe reflectivity measurements on single and double layer cuprate single crystals and thin films of ten different stoichiometries. We find that with sufficiently...
Phase diagram and electronic properties of high-T-c superconducting oxides (2003)
We firstly briefly summarize some of the most relevant recent results and open questions across rather complex electronic phase diagram of cuprates. We continue with a discussion of results on thin...
Abrecht, M., Ariosa, D., Cloetta, D., Margaritondo, G., Pavuna, D.
We use a pulsed laser deposition (PLD) setup to grow ultra-thin films of high temperature superconductors (HTSC) and transfer them in-situ into a photoemission chamber. Photoemission measurements on...
Structural phase transition in early growth of Bi2Sr2CaCu2O8+x films on SrTiO3 substrates (2002)
Abrecht, M., Ariosa, D., Onellion, M., Margaritondo, G., Pavuna, D.
We used pulsed laser deposition, with a Bi2Sr2CaCu2O8+x target, to grow films ranging from (1/4) to 10 unit cells thick. We studied these films, and reference Bi2Sr2CaCu2O8+x single crystal samples,...
Pavuna, D., Abrecht, M., Cloetta, D., Xi, X. X., Margaritondo, G., Ariosa, D.
Properties of ultra-thin films are different from their single crystal counterparts due to the presence of (substrate induced) strain, different degree and type of (growth induced) disorder and...
Ruthenocuprates RuSr2(Eu,Ce)(2)Cu2O10-y: Intrinsic magnetic multilayers (2002)
Zivkovic, I., Hirai, Y., Frazer, B. H., Prester, M., Drobac, D., Ariosa, D., ...
We report ac susceptibility data on RuSr2(Eu,Ce)(2)Cu2O10-y (Ru-1222, Ce content x=0.5 and 1.0), RuSr2GdCu2O8 (Ru-1212), and SrRuO3. Both Ru-1222 (x=0.5, 1.0) sample types exhibit unexpected magnetic...
Zivkovic, I, Drobac, D, Ariosa, D, Berger, H, Pavuna, D, Prester, M
We have measured two structurally similar superconducting systems, RuSr2GdCu2O8 and GdBa2Cu3O7 by means of high-resolution ac susceptibility. The real and the imaginary part of ac susceptibility of...
Ruthenocuprates RuSr2(Eu,Ce)2Cu2O10: Intrinsic magnetic multilayers (2001)
Zivkovic, I., Hirai, Y., Frazer, B. H., Prester, M., Drobac, D., Ariosa, D., ...
We report ac susceptibility data on RuSr_2(Eu,Ce)_2Cu_2O_(10-y) (Ru-1222, Ce content x=0.5 and 1.0), RuSr_2GdCu_2O_8 (Ru-1212) and SrRuO_3. Both Ru-1222 (x=0.5, 1.0) sample types exhibit unexpected...
On detection of the Fermi edge in in situ grown thin films of high-T-c oxides (2001)
Abrecht, M., Ariosa, D., Saleh, S. A., Rast, S., Margaritondo, G., Onellion, M., ...
We discuss our systematic series of experiments on the photoelectric detection of the Fermi edge using a cylindrical mirror analyser on films of high-T-c oxides. grown in situ by pulsed laser...
Ariosa, D., Berger, H., Schmauder, T., Pavuna, D., Margaritondo, G., Christensen, S., ...
We report on a distortion of Bi2Sr2CanCun+1 O6+2n+x (n = 0,1) single crystals, perpendicular to the CuO2 planes (the c-axis), for non-stoichiometric samples containing an excess of Bi. The distortion...
High-T-c superconductivity: new issues from photoemission data (2001)
Margaritondo, G., Grioni, M., Vobornik, I., Pavuna, D.
Recent high-resolution photoemission results on high-T-c superconductors and other low-dimensional systems solve some critical issues but also open new fundamental questions. A recent breakthrough...
On the doping variation of the pseudogap in high-T-c cuprates (2001)
Pavuna, D., Abrecht, M., Ariosa, D., Margaritondo, G.
We briefly summarize well established and the latest experimental results concerning the doping dependence of the so-called pseudogap (T*) and emphasize that surface related techniques, like ARPES or...
Figure of merit of quasicrystals: the case of Al-Cu-Fe (2001)
Bilusic, A, Pavuna, D, Smontara, A
Quasicrystals exhibit low thermal and moderate electrical conductivity, accompanied by a relatively high absolute magnitude of thermopower, which makes them suitable candidates for use as...
Evidence for two coupled subsystems in the superconducting state of La2-xSrxCuO4 (2001)
Rast, S, Schneider, ML, Onellion, M, Zeng, XH, Si, WD, Xi, XX, ...
We used a pump-probe technique to measure the transient change of optical reflectivity of both La2-xSrxCuO4, of various dopings, and slightly underdoped YBa2Cu3O7-x and NdBa2Cu3O7-x thin films. For...
High-T-c oxides 13 years since "Woodstock": From fundamentals to nanoengineering (2000)
Following introductory remarks on the "future history" of superconductivity, I discuss several discrepances concerning doping dependence of the "pseudogap" and open questions across the complex...
Pavuna, D., Vobornik, I., Margaritondo, G.
We summarize some of the main results on photoemission spectroscopy in the field of high T-c superconductivity, beginning with a discussion of several open questions. We then briefly analyze our...
Temperature-dependent photoemission features for overdoped Bi2Sr2CaCu2O8+x cuprates (2000)
Rast, S., Frazer, B. H., Onellion, M., Schmauder, T., Abrecht, M., Touzelet, O., ...
We report temperature-dependent angle-resolved photoemission spectra for overdoped Bi2Sr2CaCu2O8+alpha single-crystal samples. The data indicate that there is a special temperature (T+) where the...
On some common features in high and low-Tc superconducting perovskites (2000)
Vobornik, I., Ariosa, D., Berger, H., Forro, L., Gatt, R., Grioni, M., ...
Recent photoemission evidence for non-zero gap in highly overdoped Bi2Sr2-CaCu2O8+x, along the directions in the Brillouin zone where the d-wave gap exhibits nodes, is in accordance with more...
Disorder effects in cuprates (2000)
Vobornik, I., Grioni, M., Berger, H., Forro, L., Pavuna, D., Margaritondo, G., ...
We report on ah-plane resistivity (rho) and angle-reserved photoemission (ARPES) spectra for Bi2Sr2CaCu2O8+x single crystals irradiated with neutrons or electron-beam irradiation. Both the normal and...
Abrecht, M, Ariosa, D, Schmauder, T, Saleh, SA, Rast, S, Pavuna, D
We report on improved structural, crystallographic and electrical properties of epitaxial NdBa2Cu3O7-delta (NBCO) films grown on SrTiO3 by 'off-axis' pulsed laser deposition (PLD). Transport and XRD...
Gauzzi, A, Jonsson-Akerman, BJ, Clerc-Dubois, A, Pavuna, D
Measurements of critical temperature T-c in superconducting YBa2Cu3O6.9 films with reduced long-range structural order show the validity of the empirical scaling relation Delta T-c proportional to...
Crossovers in the out-of-plane resistivity of superconducting Tl2Ba2CaCu2O8 single crystals (2000)
Salvetat, JP, Berger, H, Halbritter, A, Mihaly, G, Pavuna, D, Forro, L
We report the in-plane (rho (ab)) and out-of-plane (rho (c)) resistivities in the 4-800 K range on single crystals of Tl2Ba2CaCu2O8 high-T-c cuprate with T-c = 111 K (rho (c)/rho (ab) approximate to...
Abrecht, M, Schmauder, T, Ariosa, D, Touzelet, O, Rast, S, Onellion, M, ...
One of the intrinsic difficulties for in situ photoemission studies of high T-c oxide films is the surface volatility, especially the oxygen loss. In order to solve this problem, we have constructed...
Gauzzi, A, Le Cochec, J, Lamura, G, Jonsson, BJ, Gasparov, VA, Ladan, FR, ...
We describe a novel single-coil mutual inductance technique for measuring the magnetic penetration depth lambda of superconductors at 2-4 MHz as a function of temperature in the 4-100 K range. We...
Ariosa, D, Abrecht, M, Pavuna, D, Onellion, M
In YBa2Cu3O6+x the tetragonal to orthorhombic transition occurs around x equals 0.3, followed by a continuum variation of lattice parameters. Hence both, the structural and superconducting...
Spectroscopic signatures of defect-induced pair breaking in Bi2Sr2CaCu2O8+x (1999)
Vobornik, I., Berger, H., Pavuna, D., Onellion, M., Margaritondo, G., Rullier-Albenque, F., ...
We investigated the effect of disorder on the spectral properties of the high temperature superconductor Bi2Sr2CaCu2O8+x. We find that small defect densities, in the low 10(-3) range, already...
Defect-induced changes in the spectral properties of high-Tc cuprates (1999)
Vobornik, I., Berger, H., Rullier-Albenque, F., Margaritondo, G., Pavuna, D., Forro, L., ...
Superconductivity in high-Tc cuprates is particularly sensitive to disorder due to the unconventional d-wave pairing symmetry. We investigated effects of disorder on the spectral properties of...
Scaling between localization length and T-c in disordered YBa2Cu3O6.9 (1999)
We quantitatively study the effect of growth-induced reduction of long range structural order on the superconducting transition in epitaxial YBa2Cu3O6.9 films. The corresponding reduction of...
First 13 years of high-T-c: Brief review and open questions (1999)
Exactly 13 years ago, in April 1986, appeared the famous paper(1) by Bednorz and Muller, that announced a striking discovery of high-T-c superconductivity in cuprates. Some 40'000 papers later, we...
Relaxation time of the Cooper pairs near T-c in cuprate superconductors (1999)
Ramallo, MV, Carballeira, C, Vina, J, Veira, JA, Mishonov, T, Pavuna, D, ...
It is first shown that the thermal fluctuation effects on the transport and on the thermodynamic observables above the superconducting transition may provide, when they are analyzed simultaneously...
On electronic and transport "anomalies" in layered oxides (1999)
We briefly discuss some electronic and transport "anomalies" observed in superconducting perovskites. In particular we consider: (i) the complex electronic (and crystallographic) phase diagram, (ii)...
Pavuna, D, Berger, H, Forro, L
We present the resistivity measurements on single crystals of Sr2RuO4-delta, grown by the flux technique. We discuss the striking, linear temperature dependence of resistivity that persists up to...
Properties of high-Tc cuprates: some recent results and open questions (1999)
Thirteen years ago, late in 1986, several groups confirmed striking claims of the famous paper by Bednorz and Muller [see Z Phys. B, vol.64, p.189 (1986)] that announced the discovery of high-Tc...
Pavuna, D., Ariosa, D., Berger, H., Christensen, S., Frazer, B., Gatt, R., ...
Due to imperfect surfaces of most cuprate samples, almost all photoemission studies in the past decade were performed on Bi2Sr2CaCu2O8+x, even though a large fraction of other studies and electronic...
Schmauder, T., Frazer, B., Gatt, R., Xi, X. X., Onellion, M., Ariosa, D., ...
We describe a new pulsed laser deposition (PLD) system that is linked to an angle-resolved photoemission (ARPES) chamber at the Synchrotron Radiation Center (SRC) in Wisconsin, USA. We also discuss...
Schmauder, T, Frazer, B, Gatt, R, Xi, X.X, Onellion, M, Ariosa, D, ...
We describe a new pulsed laser deposition (PLD) system that is linked to an angle-resolved photoemission (ARPES) chamber at the Synchrotron Radiation Center (SRC) in Wisconsin, USA. We also discuss...
On linear resistivity from ~1 to 103 K in Sr2RuO4-δ single crystals grown by flux technique (1998)
Berger, H, Forro, L, Pavuna, D
We report transport measurements on single crystals of Sr2RuO4-δ, grown by the flux technique. The temperature dependence of the Hall coefficient is similar to the one measured in cuprates, and the...
We show that the average lattice disorder in YBa2Cu3O6.9 films grown by ion-beam sputtering is homogeneous and can be quantified by introducing the lattice coherence length rc that is extracted from...
Comments on “Ion beam sputter deposition of YBa2Cu3O7-δ thin films” [and reply] (1995)
Gauzzi, A, Pavuna, D, Kellett, B.J, James, J.H
In this brief letter Gauzzi & Pavuna (GP) comment on several statements published recently in the Journal of Materials Research by their former co-workers Kellett & James (KJ) in the paper entitled...
We report on in-plane paraconductivity measurements in thin YBa2Cu3O6.9 films. Our analysis of the data shows that the temperature dependence of paraconductivity is affected by lattice disorder and...
We report evidence for the reduction of long range lattice order caused by slight departures from the optimal growth temperature in fully doped (x≈0.9) YBa2Cu3O6+x films deposited by ion-beam...
Homogeneous lattice disorder and superconducting properties of YBa2Cu3O6.9 films (1995)
We discuss the striking changes of the superconducting properties of YBa2Cu3O6.9 films to the homogeneous lattice disorder, induced by varying growth temperatures: Tc decreases with increasing...
3d X-Y scaling of the resistivity and the effect of disorder in YBa2Cu3O7-δ thin films (1994)
Wooldridge, I, Howson, M.A, Gauzzi, A, Pavuna, D, Walker, D.J.C
We present measurements for the resistivity of `c' axis oriented YBa2Cu3O7-δ (YBCO) films grown on (100) SrTiO3 substrates by both laser ablation and ion beam sputtering. The effect of the magnetic...
Studies on radiation detectors using high-Tc superconductors (1994)
Bloyet, D, Robbes, D, Langlois, P, Gilabert, A, Aboudihab, I, Kreisler, A, ...
A wide range of photodetectors has been investigated, at various wavelengths and in various time domain operating conditions (from low frequency modulated cw sources to pulsed sources). The most...
Non-universal behaviour of paraconductivity in YBa2Cu3O7-δ films (1993)
The authors analysis of in-plane paraconductivity measurements on YBa2Cu3O7-δ (YBCO) films indicates that short-wavelength cutoff effects are significant even very close to the critical point...
Preparation, processing and tunneling in YBa2Cu3O7-δ-Pb native-barrier structures (1993)
Frangi, F, Dwir, B, James, J.H, Gauzzi, A, Pavuna, D
The authors have developed a procedure for the preparation of small (40×40 μm2) window-type YBa2Cu3O7-δ-Pb junctions with YSZ insulator and native tunnel barrier. They present the patterning...
Tunneling characteristics of YBa2Cu3O7-δ-Pb window-type Josephson junctions (1992)
The authors present the results of tunneling measurements done on window-type, native-barrier YBa2Cu3O7-δ-Pb junctions. They show features in the I-V curves which are related to the gap of...
A sensitive YBaCuO thin film bolometer with ultrawide wavelength response (1992)
The authors have constructed two types of high-temperature superconducting (HTSC) bolometers, whose performance is essentially wavelength independent from λ~0.6 to 450 μm: The first is a...
Optimization of large area YBa2Cu3O7-x films by single target ion beam sputtering (1991)
Gauzzi, A, Lucia, M.L, Affronte, M, Pavuna, D
The authors report on the in-situ growth over large area of high-quality homogeneous YBa2Cu3O7-x films by single target ion beam sputtering. The 123 stoichiometry transfer to the substrates is...
Evidence for improvement of critical current by Ag in YBaCuO-Ag thick films (1991)
Dwir, B, Kellett, B, Mieville, L, Pavuna, D
The evidence is reported for enhancement of critical current density Jc in YBa2Cu3O7-δ thick films with the addition of Ag, which is correlated with improvements in structural properties. An...
Window-type tunnel devices on YBa2Cu3O7-x thin films (1991)
James, J.H, Dwir, B, Affronte, M, Munzner, A, Naucler, T, Kellet, B.J, ...
The authors present the first YBa2Cu3O7-x-Pb tunnelling measurements using window-type tunnel devices. YBa2Cu3O7-x (YBCO) thin films are grown in-situ by dual Ar+ ion beam sputtering. Tunnel barriers...
Large area superconducting YBa2Cu3O7-x films grown by single target ion beam sputtering (1991)
Gauzzi, A, Lucia, M.L, Kellett, B, Ames, J.H, Pavuna, D
The authors have demonstrated, by using a simple single YBa2Cu3O7-x target ion beam system that, with a sufficiently low power ion beam, preferential sputtering is avoided and high-quality...
Microstructure and electrical properties of pure 110 K phase in the BiPbSrCaCuO system (1991)
Holguin, E, Berger, H, Levy, F, Dwir, B, Pavuna, D, Burri, G
The temperature dependence of the DC resistivity and AC magnetic susceptibility was investigated in bulk ceramics of the BiPbSrCaCuO system with 2212-free (2223) phase. The temperature domain needed...
Kellett, B.J, James, J.H, Gauzzi, A, Dwir, B, Pavuna, D, Reinhart, F.K
Superconducting YBa2Cu3O7-δ (YBCO) thin films have been grown in situ on Si with conducting indium-tin-oxide (ITO) buffer layers. ITO allows YBCO to be electrically connected to the underlying Si...
Superconducting YBa2Cu3O7-δ thin films on GaAs with conducting indium-tin-oxide buffer layers (1990)
Kellett, B.J, Gauzzi, A, James, J.H, Dwir, B, Pavuna, D, Reinhart, F.K
Superconducting YBa2Cu3O7-δ (YBCO) thin films have been grown in situ on GaAs with conducting indium-tin-oxide (ITO) buffer layers. Superconducting onset is about 92 K with zero resistance at 60 K....
Zn doping of YBCO and hall effect study in Y1Ba2(Cu1-xZnx)3O7-δ (1989)
Affronte, M, Pavuna, D, Francois, M, Licci, F, Besagni, T, Cattani, S
Long-exposure photographs taken with a Guinier camera on powders of Zn doped YBCO indicate incomplete inclusion of Zn in YBCO for x>=0.05. The study of the temperature dependence of the Hall number...
Magnetic and transport properties of superconducting (YBa2Cu3O7-δ)1-xAgx ceramics (1989)
Laborde, O, Souletie, B, Guillot, M, Capponi, J.J, Lejay, P, Tholence, J.L, ...
The introduction of silver in the intergranular space of YBa2Cu3O7 ceramics improves their normal state electrical and mechanical properties. The authors report a study of such composites of which...
Critical current and electronic properties of YBCO-Ag compounds (1989)
Dwir, B, Affronte, M, Pavuna, D
We have found that in YBCO-Ag ceramic compounds Ag fills the intergranular space ('holes') without affecting Tc. Normal-state resistivity is decreased by approximately equals × 100 when adding up to...
Superconducting YBa2Cu3O7 thin films grown in-situ by ion beam co-deposition (1989)
Kellett, B.K, James, J.H, Gauzzi, A, Owir, B, Pavuna, D
Superconducting YBCO thin films have been grown in-situ by three ion beam co-deposition sputtering. Both metal and oxide targets of Cu and Y and BaF2 and BaCO3 targets have been investigated. Film...
In-situ superconducting YBa2Cu3O7 thin films grown by ion beam co-deposition (1989)
James, J.H, Kellett, B.J, Gauzzi, A, Dwir, B, Pavuna, D
The authors present superconducting YBa2C3O7 (YBCO) thin films grown in-situ by three-ion-beam sputtering. Y, Y2O3, Cu, Cu2O, BaF2 and BaCO3 sputter targets have been investigated. The highest...
A simple high-temperature superconducting thin-film optical bolometer (1989)
Dwir, B, Pavesi, L, James, J.H, Kellett, B, Pavuna, D, Reinhart, F.K
The authors have demonstrated the operation of a simple optical bolometer by irradiating a constriction in a Y1Ba2Cu3O7-δ thin film with chopped laser light at λ=633 nm. The change in film...
Evidence for enhancement of critical current by intergrain Ag in YBaCuO-Ag ceramics (1989)
Dwir, B, Affronte, M, Pavuna, D
The authors report the evidence for enhancement of critical current density Jc by ~50%, which occurs when ~10 wt.% Ag is added to Y1Ba2Cu3O7-δ ceramics. The maximal Jc (~700 A/cm2 at T=77 K) appears...
High-temperature transformation in AlMn(Si) quasi-crystals (1989)
Berger, C, Cyrot-Lackmann, F, Devenyi, J, Fourcaudot, G, Germi, P, Grieco, J.C, ...
Transformations of the quasi-crystalline icosahedral phases formed in the melt-spun AlMn(Si) alloys Al90Mn10, Al86Mn14 and Al75Mn20Si5 have been studied at high temperatures (300-1000 K) by combined...
Radio frequency penetration depth in HTSC ceramic samples (1989)
Gasparov, V.A, Huguenin, R, Pavuna, D
The authors present measurements of the temperature dependence of the RF penetration depth δ(T) in YBa2Cu3O6.9 and BiSrCaCu2Ox ceramics. They found that δ(T) closely follows the Gorter-Casimir...
Dwir, B, Pavuna, D, Affronte, M, Berger, H, Tholence, J.L
The authors present the percolation and electronic properties of (Y1Ba2Cu3O7-δ)1-xAgx compounds in which silver fills the intergranular space without reducing Tc, which remains at 92±1 K....
Effects of Cu substitution by Zn on transport properties of Y1Ba2Cu3O7-δ (1989)
Affronte, M, Pavuna, D, Martin, O, Licci, F, Besagni, T, Cattani, S
The authors report the temperature dependence of resistivity and the Hall coefficient RH of a series of Y1Ba2(Cu1-xZnx)3O7-δ ceramics with x up to 0.075. In all their samples they have observed...
Preparation of YBCO thin films by a four ion beam co-deposition system (1989)
Michel, S, James, J.H, Dwir, B, Affronte, M, Kellett, B, Pavuna, D
We present preliminary results for thin films grown with a recently commissioned ion beam codeposition system designed for in situ growth and etching of YBCO films. The apparatus consists of a...
Ion beam sputtering and properties of YBaCuO superconducting thin films (1988)
Pavuna, D, Baer, W, Berger, H, Mathieu, H.J, Vogel, A, Schmidt, M, ...
The authors have produced YBaCuO thin films by mono-target ion beam sputtering. Post annealing in O2 at 850°C results in superconducting films on (100) SrTiO3 with R=0 at ~60 K. Preliminary results...
Low temperature calorimetric and magnetic properties of Al-Mn and Al-Mn-Si quasi-crystals (1988)
Lasjaunias, J.C, Paulsen, C, Godinho, M, Berger, C, Pavuna, D
The authors report the low temperature specific heat Cp and magnetic measurements for solid solution Al-3at.percent Mn, Al86Mn14 and Al25Mn20Si5 in quasi-crystalline phases. From the amplitude of the...
Electronic properties and (meta) stability of rapidly quenched Al-Si alloys (1988)
Chevrier, J, Pavuna, D, Cyrot-Lackmann, F
Two important effects were found in rapidly quenched Al-Si alloys: (i) the enhancement of the electron-phonon coupling parameter, revealed by the variation of Tc and the slope of thermal resistivity;...
Pavuna, D, Berger, H, Affronte, M, Capponi, J.J, Guillot, M, ...
The authors present electronic properties and critical current densities (jc at 4.2 K, up to 18 T) of (Y1Ba2Cu3O6.9)1-xAgx compounds in which silver fills the intergranular space without reducing Tc...
Electronic properties and resonant states in Al-Mn(-Si) alloys (1988)
Berger, C, Pavuna, D, Cyrot-Lackmann, F, Cyrot, M
Experimental studies of quasi-crystalline Al100-xMnx(Si) alloys have shown that the magnitude of electrical resistivity as well as the excess specific heat term Δγ are proportional to the...
On electronic properties of Al-Mn(-Si) quasicrystals (1988)
Pavuna, D, Berger, C, Cyrot-Lackmann, F
The authors present structural and resistivity studies of the melt-spun Al-Mn (10-20 at.% Mn) alloys which contain more than 50 vol.% of the quasicrystalline (QC) phase. Using a two-phase Landauer...
Berger, C, Lasjaunias, J.C, Tholence, J.L, Pavuna, D, Germi, P
The authors report experimental evidence for an enhanced density of states at the Fermi level in Al86Mn14 and Al75Mn20Si5 quasicrystals (QC) as indicated by the low-temperature specific heat and...
Localization effects in amorphous alloys under high magnetic field (1988)
Ousset, J.C, Broto, J.M, Rakoto, H, Dupuis, V, Durand, J, Marchal, G, ...
Magnetoresistance measurements on metallic amorphous alloys constitute a good tool to study Anderson localization effects in three dimensional systems. The authors have performed measurements under...
Electronic properties of superconducting (YBa2 Cu3O6.9)1-xAgx compounds (1988)
Pavuna, D, Berger, H, Affronte, M, Sanjines, R, Dubas, A, ...
We have studied electronic properties of (YBa2Cu3O6.9)1-xAgx compounds with 5, 10, 15, 25 and 50 wt% Ag. In our samples, the silver fills the intergranular space and the superconductivity is...
IMPROVED LOW CONTACT RESISTANCE IN HIGH-T//c Y-Ba-Cu-O CERAMIC SUPERCONDUCTORS. (1987)
One of the important problems for electrical applications of high-temperature superconductors is the contact resistance between the superconductor and a normal metallic wire. In this paper, the...
Glick, M, Pavuna, D, Reinhart, F. K
We report phase difference measurements at 50 and 30 mev from the excitonic peak of a GaAs/AlGaAs multiquantum-well structure. We find pronounced dispersion of the quadratic effect; in contrast, we...
Electronic properties and superconductivity of rapidly quenched Al-Si alloys (1987)
Chevrier, J, Pavuna, D, Cyrot-Lackmann, F
The authors present detailed studies of electronic properties of Al-Si alloys prepared in a nonequilibrium state by means of rapid solidification. The quenched alloys exhibit an enhanced...
Lasjaunias, J. C, Tholence, J. L, Berger, C, Pavuna, D
Low temperature specific heat and ac susceptibility studies on quasicrystalline Al//8//6Mn//1//4 and Al//7//5Mn//2//0Si//5 show that most Mn's are nonmagnetic. The fraction of magnetic Mn's (about...
Ousset, J.C, Rakoto, H, Broto, J.M, Dupuis, V, Durand, J, Marchal, G, ...
The authors present measurements of the temperature dependence of the upper critical field Hc2 and of the magnetoresistance for V1-xSix superconducting amorphous alloys. Negative deviations from the...
ON ELECTRONIC PROPERTIES OF Al-Mn QUASICRYSTALS (1986)
Berger, C., Pavuna, D., Cyrot-Lackmann, F.
We present the results on structural and electronic properties of the melt-spun Al-Mn alloys (10 to 18 at% Mn) which contain more than 50 vol% of the quasicrystalline (qX) phase. The analysis of our...
Electronic structure and sign reversal of the Hall coefficient in amorphous CuZr alloys (1986)
Manh, D.N, Pavuna, D, Cyrot-Lackmann, F, Mayou, D, Pasturel, A
The authors present calculated densities of states (DOS) for CuxZr1-x amorphous alloys across the compositional range. They find that for x
ON ELECTRONIC PROPERTIES OF Al//4Mn QUASICRYSTALS IN MELT-SPUN Al-Mn ALLOYS. (1986)
Pavuna, D, Berger, C, Cyrot-Lackmann, F, Germi, P, Pasturel, A
We present the resitivity and structural studies of the melt-spun Al-Mn alloys (with 10-18 at% Mn) that contain more than 50 vol% of the quasicrystalline (qX) Al//4Mn phase. The resistivity varies...
ON ELECTRONIC PROPERTIES OF Al-Mn QUASICRYSTALS (1986)
Berger, C., Pavuna, D., Cyrot-Lackmann, F.
We present the results on structural and electronic properties of the melt-spun Al-Mn alloys (10 to 18 at% Mn) which contain more than 50 vol% of the quasicrystalline (qX) phase. The analysis of our...
ON ELECTRONIC PROPERTIES OF Al-Mn QUASICRYSTALS (1986)
Berger, C., Pavuna, D., Cyrot-Lackmann, F.
We present the results on structural and electronic properties of the melt-spun Al-Mn alloys (10 to 18 at% Mn) which contain more than 50 vol% of the quasicrystalline (qX) phase. The analysis of our...
INFLUENCE OF RAPID QUENCHING AND SAMPLE TREATMENT ON THE STRUCTURE OF MELT SPUN Al-Si ALLOYS (1985)
Chevrier, J., Sainfort, P., Germi, P., Pavuna, D.
We have studied the structural characteristics of the range of melt spun Al-Si alloys. We find that the dominant feature is the existence of sursaturated Si in f.c.c. Al grains which well explains...
INFLUENCE OF RAPID QUENCHING AND SAMPLE TREATMENT ON THE STRUCTURE OF MELT SPUN Al-Si ALLOYS (1985)
Chevrier, J., Sainfort, P., Germi, P., Pavuna, D.
We have studied the structural characteristics of the range of melt spun Al-Si alloys. We find that the dominant feature is the existence of sursaturated Si in f.c.c. Al grains which well explains...
INFLUENCE OF RAPID QUENCHING AND SAMPLE TREATMENT ON THE STRUCTURE OF MELT SPUN Al-Si ALLOYS (1985)
Chevrier, J., Sainfort, P., Germi, P., Pavuna, D.
We have studied the structural characteristics of the range of melt spun Al-Si alloys. We find that the dominant feature is the existence of sursaturated Si in f.c.c. Al grains which well explains...