High-temperature phases of YBa2Cu3O6+x related to the superconducting transition

1988 ◽  
Vol 7 (5) ◽  
pp. 489-492 ◽  
Author(s):  
L. Papadimitriou ◽  
O. Valassiades ◽  
K. Manolikas ◽  
J. Stoemenos ◽  
J. Spyridelis ◽  
...  
Keyword(s):  
High Temperature ◽  
Superconducting Transition

scholarly journals Enhancing Superconductivity of the Nonmagnetic Quasiskutterudites by Atomic Disorder

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5830
Author(s):  
Andrzej Ślebarski ◽  
Maciej M. Maśka
Keyword(s):  
High Temperature ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
High Temperature Superconductors ◽  
Superconducting Phase ◽  
Length Scale ◽  
Superconducting Transition ◽  
Atomic Disorder ◽  
Strong Inhomogeneity ◽  
Related Compounds

We investigated the effect of enhancement of superconducting transition temperature Tc by nonmagnetic atom disorder in the series of filled skutterudite-related compounds (La3M4Sn13, Ca3Rh4Sn13, Y5Rh6Sn18, Lu5Rh6Sn18; M= Co, Ru, Rh), where the atomic disorder is generated by various defects or doping. We have shown that the disorder on the coherence length scale ξ in these nonmagnetic quasiskutterudite superconductors additionally generates a non-homogeneous, high-temperature superconducting phase with Tc⋆>Tc (dilute disorder scenario), while the strong fluctuations of stoichiometry due to increasing doping can rapidly increase the superconducting transition temperature of the sample even to the value of Tc⋆∼2Tc (dense disorder leading to strong inhomogeneity). This phenomenon seems to be characteristic of high-temperature superconductors and superconducting heavy fermions, and recently have received renewed attention. We experimentally documented the stronger lattice stiffening of the inhomogeneous superconducting phase Tc⋆ in respect to the bulk Tc one and proposed a model that explains the Tc⋆>Tc behavior in the series of nonmagnetic skutterudite-related compounds.

scholarly journals Superconducting Accelerator Magnets Based on High-Temperature Superconducting Bi-2212 Round Wires

Instruments ◽  
2020 ◽  
Vol 4 (2) ◽  
pp. 17
Author(s):  
Tengming Shen ◽  
Laura Garcia Fajardo
Keyword(s):  
High Temperature ◽  
High Field ◽  
Scientific Discovery ◽  
Superconducting Magnets ◽  
Hadron Collider ◽  
Development Program ◽  
High Energy ◽  
Superconducting Transition ◽  
High Temperature Superconducting ◽  
Superconducting Accelerator

Superconducting magnets are an invaluable tool for scientific discovery, energy research, and medical diagnosis. To date, virtually all superconducting magnets have been made from two Nb-based low-temperature superconductors (Nb-Ti with a superconducting transition temperature Tc of 9.2 K and Nb3Sn with a Tc of 18.3 K). The 8.33 T Nb-Ti accelerator dipole magnets of the large hadron collider (LHC) at CERN enabled the discovery of the Higgs Boson and the ongoing search for physics beyond the standard model of high energy physics. The 12 T class Nb3Sn magnets are key to the International Thermonuclear Experimental Reactor (ITER) Tokamak and to the high-luminosity upgrade of the LHC that aims to increase the luminosity by a factor of 5–10. In this paper, we discuss opportunities with a high-temperature superconducting material Bi-2212 with a Tc of 80–92 K for building more powerful magnets for high energy circular colliders. The development of a superconducting accelerator magnet could not succeed without a parallel development of a high performance conductor. We will review triumphs of developing Bi-2212 round wires into a magnet grade conductor and technologies that enable them. Then, we will discuss the challenges associated with constructing a high-field accelerator magnet using Bi-2212 wires, especially those dipoles of 15–20 T class with a significant value for future physics colliders, potential technology paths forward, and progress made so far with subscale magnet development based on racetrack coils and a canted-cosine-theta magnet design that uniquely addresses the mechanical weaknesses of Bi-2212 cables. Additionally, a roadmap being implemented by the US Magnet Development Program for demonstrating high-field Bi-2212 accelerator dipole technologies is presented.

Crystal Growth of High Temperature Superconductors

MRS Bulletin ◽  
1988 ◽  
Vol 13 (10) ◽  
pp. 56-61 ◽  
Author(s):  
H.J. Scheel ◽  
F. Licci
Keyword(s):  
High Temperature ◽  
Critical Current Density ◽  
Single Crystals ◽  
Critical Current ◽  
Current Density ◽  
Large Scale ◽  
High Temperature Superconductivity ◽  
High Temperature Superconductors ◽  
Superconducting Transition ◽  
Theoretical Understanding

The discovery of high temperature superconductivity (HTSC) in oxide compounds has confronted materials scientists with many challenging problems. These include the preparation of ceramic samples with critical current density of about 106 A/cm2 at 77 K and sufficient mechanical strength for large-scale electrotechnical and magnetic applications and the preparation of epitaxial thin films of high structural perfection for electronic devices.The main interest in the growth of single crystals is for the study of physical phenomena, which will help achieve a theoretical understanding of HTSC. Theorists still do not agree on the fundamental mechanisms of HTSC, and there is a need for good data on relatively defect-free materials in order to test the many models. In addition, the study of the role of defects like twins, grain boundaries, and dislocations in single crystals is important for understanding such parameters as the critical current density. The study of HTSC with single crystals is also expected to be helpful for finding optimum materials for the various applications and hopefully achieving higher values of the superconducting transition temperature Tc than the current maximum of about 125 K. It seems unlikely at present that single crystals will be used in commercial devices, but this possibility cannot be ruled out as crystal size and quality improve.

scholarly journals Higher superconducting transition temperature by breaking the universal pressure relation

2019 ◽  
Vol 116 (6) ◽  
pp. 2004-2008 ◽  
Author(s):  
Liangzi Deng ◽  
Yongping Zheng ◽  
Zheng Wu ◽  
Shuyuan Huyan ◽  
Hung-Cheng Wu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
High Temperature ◽  
Transition Temperature ◽  
Density Functional ◽  
High Temperature Superconductors ◽  
Density Functional Theory Calculations ◽  
Universal Relation ◽  
Superconducting Transition ◽  
Functional Theory ◽  
A Charge

By investigating the bulk superconducting state via dc magnetization measurements, we have discovered a common resurgence of the superconducting transition temperatures (Tcs) of the monolayer Bi2Sr2CuO6+δ(Bi2201) and bilayer Bi2Sr2CaCu2O8+δ(Bi2212) to beyond the maximum Tcs (Tc-maxs) predicted by the universal relation between Tcand doping (p) or pressure (P) at higher pressures. The Tcof underdoped Bi2201 initially increases from 9.6 K at ambient to a peak at 23 K at 26 GPa and then drops as expected from the universal Tc-P relation. However, at pressures above 40 GPa, Tcrises rapidly without any sign of saturation up to 30 K at 51 GPa. Similarly, the Tcfor the slightly overdoped Bi2212 increases after passing a broad valley between 20 and 36 GPa and reaches 90 K without any sign of saturation at 56 GPa. We have, therefore, attributed this Tcresurgence to a possible pressure-induced electronic transition in the cuprate compounds due to a charge transfer between the Cu 3dx2−y2and the O 2pbands projected from a hybrid bonding state, leading to an increase of the density of states at the Fermi level, in agreement with our density functional theory calculations. Similar Tc-P behavior has also been reported in the trilayer Br2Sr2Ca2Cu3O10+δ(Bi2223). These observations suggest that higher Tcs than those previously reported for the layered cuprate high-temperature superconductors can be achieved by breaking away from the universal Tc-P relation through the application of higher pressures.

Volume dependence of the superconducting transition temperature for the high-temperature superconductorHgBa2Ca2−xPbxCu3O8+δ

1994 ◽  
Vol 50 (18) ◽  
pp. 13778-13785 ◽  
Author(s):  
Charles C. Kim ◽  
A. R. Drews ◽  
E. F. Skelton ◽  
S. B. Qadri ◽  
M. S. Osofsky ◽  
...  
Keyword(s):  
High Temperature ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Superconducting Transition ◽  
Volume Dependence

Phase relations and superconducting properties of the Y–Ni–B–C system

1999 ◽  
Vol 14 (1) ◽  
pp. 16-23 ◽  
Author(s):  
G. Behr ◽  
W. Löser ◽  
G. Graw ◽  
K. Nenkov ◽  
U. Krämer ◽  
...  
Keyword(s):  
High Temperature ◽  
Intermetallic Phase ◽  
Phase Relations ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
Residual Resistance ◽  
High Temperature Heat Treatment ◽  
Temperature Heat ◽  
Temperature Heat Treatment

The influence of composition and high-temperature heat treatment on phase content and superconducting properties of the Yni2B2C phase was investigated. Phase relations in those parts of the Y–Ni–B–C quaternary phase diagram, which are relevant for the YNi2B2C intermetallic phase formation, were revealed by x-ray diffraction, optical and scanning electron microscopy, and high-temperature differential thermoanalysis. A widespread interval of superconducting transition temperatures TC = 10.4–15.2 K and small transition width <0.3 K were determined from samples of different nominal compositions after high-temperature annealing. The different intrinsic properties are ascribed to composition variations of the YNi2B2C phase and related to structure parameters, residual resistance ratios, and element concentrations determined by the electron probe microanalysis.

High Pressure High Temperature (HPHT) Synthesis and Physical Characterization of Magneto-Superconducting RuSr2Tb1.5Ce0.5Cu2O10 Ceramic Compound

2006 ◽  
Vol 47 ◽  
pp. 31-36
Author(s):  
Alberto Ubaldini ◽  
V.P.S. Awana ◽  
S. Balamurugan ◽  
E. Takayama-Muromachi
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Magnetic Transition ◽  
Magnetic Ordering ◽  
Superconducting Transition ◽  
Synthesis Conditions ◽  
High Pressure High Temperature ◽  
Interesting Class ◽  
Ceramic Compound

The ruthenocuprates family is a very interesting class of materials, because of the coexistence of superconductivity and magnetic ordering. Ruthenocuprates include RuSr2RECu2O8 and RuSr2(RE,Ce)2Cu2O10- (RE = rare earth elements or Y). It is possible to synthesize samples of these phases with Gd, Eu or Sm with normal synthesis conditions. For the others high-pressure high-temperature (HPHT) synthesis is required. We had successfully synthesized the RuSr2Tb1.5Ce0.5Cu2O10 by HPHT technique, starting from RuO2, SrO2, Tb4O7, CeO2, CuO and Cu. Around 300 mg of the mixture was allowed to react in a flat-belt-typehigh- pressure apparatus at 6GPa and 1200 °C – 1550 °C. The optimised temperature of synthesis was found to be in the range between 1350 °C – 1450 °C. The as-synthesized compound crystallized with a structure belonging to the space group I4/mmm. DC magnetic susceptibility versus temperature plot for RuSr2Tb1.5Ce0.5Cu2O10 in an applied field of 10 Oe demonstrated magnetic transition at 150 K but the superconducting transition was not clearly observed. To our knowledge this is the first successful synthesis of the Tb based Ru-1222 phase.

Study of the Effect of Oxygen Annealing on YBCO Platelet Aggregates Synthesized by a Biomimetic Method

2013 ◽  
Vol 834-836 ◽  
pp. 437-441
Author(s):  
Zi Li Zhang ◽  
Hong Li Suo ◽  
Ahmed Kursumovic ◽  
Min Liu ◽  
Yi Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxygen Deficiency ◽  
Superconducting Transition ◽  
Oxygen Annealing ◽  
High Temperature Anneal ◽  
Structural And Electrical Properties ◽  
Platelet Aggregates ◽  
Biomimetic Method ◽  
Pre Treatment ◽  
Effect Of Oxygen

The effect of different oxygen annealing treatments on the structural and electrical properties of samples of the high temperature superconductor YBa2Cu3O7δ(YBCO) synthesized by a biomimetic method has been studied. By oxygen annealing, the oxygen deficiency resulting from the synthesis in air can be adequately compensated. A two-stage annealing process including a high temperature step results in a sharper superconducting transition and higher critical current density of the YBCO than annealing only at low temperature, due to the additional elimination of carbon residues from the biopolymer additive. To avoid the formation of impurity phases resulting from decomposition of the YBCO during the high-temperature anneal, careful pre-treatment by rinsing the as-synthesized YBCO with distilled water to remove residual NaCl is necessary.

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