Origin of the 110-K superconducting transition in the Bi-Sr-Ca-Cu-O system (original) (raw)
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A correlation has been found between the Cu 3+-ion/oxygen deficiency positions in the CuO 2 plane and the critical transition temperature T c in the high temperature superconducting (HTSC) material YBa 2 Cu 3 O 7−. Two modes are responsible for the two transition temperatures at 93 and 57 K given by deficiency values of 0.04 and 0.45, respectively.
Evidence of precursor superconductivity as high as 180 K from infrared spectroscopy
We show that a multilayer analysis of the infrared c-axis response of RBa2Cu3O7-d (R=Y, Gd, Eu) provides important new information about the anomalous normal state properties of underdoped cuprate high temperature superconductors. Besides competing correlations which give rise to a pseudogap that depletes the low-energy electronic states below T*>>Tc, it enables us to identify the onset of a precursor superconducting state below Tons>Tc. We map out the doping phase diagram of Tons which reaches a maximum of ~180 K at strong underdoping and present magnetic field dependent data which confirm our conclusions.
Physical Review Letters, 1987
Transition to a superconducting zero-resistance state at 155 K is observed for the first time in bulk material. A new five-element compound has been synthesized with nominal composition YIBa2Cu3F20y. Fluorine plays a critical role in achieving this eAect. X-ray diffraction and electron microprobe analysis indicate that the samples are multiphasic. Evidence is presented that the samples contain superconducting phases with onset temperatures considerably above 155 K. Magnetic measurements suggest a fluxtrapping eftect below 260 K, and diamagnetic deviations from Curie-Weiss behavior in the range 250 K~T~100 K indicate a Meissner efect in a small superconducting volume fraction.
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The correct nature of high-T C superconductivity is outlined: (i) the cuprates do not superconduct in their cuprate-planes, but in their BaO, SrO, or interstitial-oxygen regions; (ii) doped Ba 2 YRuO 6 and Sr 2 YRuO 6 , ruthenates without cuprate-planes, superconduct in their BaO or SrO layers; (iii) the rutheno-cuprates GdSr 2 Cu 2 RuO 8 and Gd 2−z Ce z Sr 2 Cu 2 RuO 10 have cuprate-planes which do not superconduct, but superconduct in their SrO layers; (iv) LaFeAsO 1−x F x superconducts via its oxygen ions, as do related compounds; and (v) the organic compound κ-[BEDT-TTF] 2 Cu[NCS] 2 superconducts along the S chains of the molecule. In YBa 2 Cu 3 O 7 , the superconductivity is consistent with observations by positive muon spin rotation and with analyses indicating an absence of Cu d-band contribution to the superconductivity. Hence only, the BaO layer superconducts. The superconductivity is s-wave in character (not d-wave), once fluxon depinning has been properly accounted for. The superconducting BaO layers are p-type and adjacent to the n-type cuprate-planes. The hole-pairing is not phononic, but Coulombic. Many experiments can be
Physica C: Superconductivity, 1988
The effect of the annealing conditions on the superconductive transitions in Bi-Sr-Ca-Cu-O samples of various compositions has been studied by a.c. susceptibility. It is confirmed that the annealing conditions are very critical, in particular for the observation of the "l l0 K" transition. For the nominal composition 1 : 1 : 1:2, bulk samples in which the 110 K transition amplitude attains up to 40% of the full amplitude have been obtained. The magnetization of these samples is reported. A thermal treatment under vacuum in mild conditions has a dramatic effect on the amplitude and the onset temperature of the 110 K transition. Initial values are readily restored by a short annealing under oxygen flow at low temperature, giving strong evidence for a reversible oxygen uptake as previously observed in the YBaCuO family.
Superconducting materials are characterized by the fact that they lose their electrical resistance below a certain temperature, the so-called transition temperature. [35]
Superconductivity at 105 K inTl0.5Pb0.5CaSr2-xLaxCu2O7
Physica C: Superconductivity, 1991
Substitution of La3+ for S?' in the lattice T&Pb0.$SrzCaCu20, has been used to reduce the hole carrier concentration on the Cu02 planes resulting in r, passing through a maximum at 105 K. This behaviour is similar to the previously reported effect of substitution of Y3+ for Ca2+ m the same parent material. However, in the La3+-substituted series: (a) superconductivity is maintained to higher substitution levels; (b) the c-axis lattice parameter initially contracts at only 30% of the rate; and (c) the ab-planes lattice parameter expands at 140% of the rate; compared to the Y3+-substituted series. These effects are consequences of the differing sites of substitution-La'+ on the Q-0 plane bounding the CuOz planes, and hence influencing the bridging oxygen atom; Y3+ on the bare Ca*+ site between the CuOr planes. The superconducting phase diagrams of T, versus substitution level are similar to the phase diagram for the Cu02 planes established for Lar_>r,CuO.
High-temperature superconductivity
Journal of Magnetism and Magnetic Materials, 1998
The current status of basic research on the high temperature cuprate superconductors and prospects for technological applications of these materials is discussed. Recent developments concerning other novel superconductors are also briefly described.
Superconductivity up to 110 K in Bi2Sr2Ca2Cu3O10 compounds
Revue de Physique Appliquée, 1989
2014 Nous avons étudié dans le système Bi-Si-Ca-Cu-O le composé responsable de la supraconductivité jusqu'à 110 K, de formule idéale Bi2Sr2Ca2Cu3O10. Les mesures d'aimantation montrent la présence de deux phases dans les échantillons, avec des transitions à 80 K et 110 K. En faisant varier la composition et les traitements thermiques de ces échantillons, nous avons réussi à augmenter la proportion de la phase supraconductrice jusqu'à 110 K. L'effet Meissner atteint 30 % de -3/8 03C0 à 90 K pour les échantillons non dopés et 50 % pour ceux dopés au plomb. La grande réversibilité des courbes d'aimantation en fonction du champ au voisinage de Tc nous a permis d'évaluer le champ critique thermodynamique. Celui-ci conduit à un coefficient de chaleur spécifique électronique similaire à celui des composés YBaCuO. Abstract. 2014 In the Bi-Sr-Ca-Cu-O system, we have studied the compound with the ideal formula Bi2Sr2Ca2Cu3O10, responsible for the superconductivity up to 110 K. The magnetic measurements reveal the presence of two phases in the samples with superconducting transitions up to 80 K and 110 K. By varying the composition and the thermal treatment of those samples, we have succeeded in increasing the amount of the superconducting phase with Tc up to 110 K. The Meissner effect reaches 30 % of -3/8 03C0 at 90 K for the undoped samples and more than 50 % for the samples doped with Pb. Because of the high reversibility of the magnetization versus magnetic field around Tc, we have evaluated the critical thermodynamic field. This one gives an electronic specific heat coefficient similar to the one of YBaCuO compounds. Revue Phys. Appl. 24 (1989) 485-488 MAI 1989, Classification Physics Abstracts 74.70 Introduction.