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Title: Optical And Thermodynamic Properties of the High-Temperature Superconductor HgBa2CuO4+Delta

Abstract

No abstract prepared.

Authors:
; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC)
Sponsoring Org.:
USDOE
OSTI Identifier:
901835
Report Number(s):
SLAC-REPRINT-2007-019
Journal ID: ISSN 0163-1829; PRBMDO; TRN: US200717%%83
DOE Contract Number:
AC02-76SF00515
Resource Type:
Journal Article
Resource Relation:
Journal Name: Phys. Rev. B75:054522,2007; Journal Volume: 75
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; BARIUM OXIDES; COPPER OXIDES; HIGH-TC SUPERCONDUCTORS; MERCURY OXIDES; OPTICAL PROPERTIES; SUPERCONDUCTORS; THERMODYNAMIC PROPERTIES; Other,OTHER

Citation Formats

Heumen, E.van, Lortz, R., Kuzmenko, A.B., Carbone, F., Marel, D.van der, Zhao, X., Yu, G., Cho, Y., Barisic, N., Greven, M., Homes, C.C., and Dordevic, S.V. Optical And Thermodynamic Properties of the High-Temperature Superconductor HgBa2CuO4+Delta. United States: N. p., 2007. Web. doi:10.1103/PhysRevB.75.054522.
Heumen, E.van, Lortz, R., Kuzmenko, A.B., Carbone, F., Marel, D.van der, Zhao, X., Yu, G., Cho, Y., Barisic, N., Greven, M., Homes, C.C., & Dordevic, S.V. Optical And Thermodynamic Properties of the High-Temperature Superconductor HgBa2CuO4+Delta. United States. doi:10.1103/PhysRevB.75.054522.
Heumen, E.van, Lortz, R., Kuzmenko, A.B., Carbone, F., Marel, D.van der, Zhao, X., Yu, G., Cho, Y., Barisic, N., Greven, M., Homes, C.C., and Dordevic, S.V. Fri . "Optical And Thermodynamic Properties of the High-Temperature Superconductor HgBa2CuO4+Delta". United States. doi:10.1103/PhysRevB.75.054522.
@article{osti_901835,
title = {Optical And Thermodynamic Properties of the High-Temperature Superconductor HgBa2CuO4+Delta},
author = {Heumen, E.van and Lortz, R. and Kuzmenko, A.B. and Carbone, F. and Marel, D.van der and Zhao, X. and Yu, G. and Cho, Y. and Barisic, N. and Greven, M. and Homes, C.C. and Dordevic, S.V.},
abstractNote = {No abstract prepared.},
doi = {10.1103/PhysRevB.75.054522},
journal = {Phys. Rev. B75:054522,2007},
number = ,
volume = 75,
place = {United States},
year = {Fri Apr 06 00:00:00 EDT 2007},
month = {Fri Apr 06 00:00:00 EDT 2007}
}
  • In- and out-of-plane optical spectra and specific heat measurements for the single layer cuprate superconductor HgBa{sub 2}CuO{sub 4+{delta}} (Hg-1201) at optimal doping (T{sub c} = 97 K) are presented. Both the in-plane and out-of-plane superfluid density agree well with a recently proposed scaling relation {rho}{sub s} {proportional_to} {sigma}{sub dc} T{sub c}. It is shown that there is a superconductivity induced increase of the in-plane low frequency spectral weight which follows the trend found in underdoped and optimally doped Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} (Bi-2212) and optimally doped Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10+{delta}} (Bi-2223). We observe an increase of opticalmore » spectral weight which corresponds to a change in kinetic energy {Delta}W {approx} 0.5 meV/Cu which is more than enough to explain the condensation energy. The specific heat anomaly is 10 times smaller than in YBa{sub 2}Cu{sub 3}O{sub 6+{delta}} (YBCO) and 3 times smaller than in Bi-2212. The shape of the anomaly is similar to the one observed in YBCO showing that the superconducting transition is governed by thermal fluctuations.« less
  • The compound HgBa{sub 2}CuO{sub 4+{delta}} (Hg1201) exhibits a simple tetragonal crystal structure and the highest superconducting transition temperature (T{sub c}) among all single Cu-O layer cuprates, with T{sub c} = 97 K (onset) at optimal doping. Due to a lack of sizable single crystals, experimental work on this very attractive system has been significantly limited. Thanks to a recent breakthrough in crystal growth, such crystals have now become available. Here, we demonstrate that it is possible to identify suitable heat treatment conditions to systematically and uniformly tune the hole concentration of Hg1201 crystals over a wide range, from very underdopedmore » (T{sub c} = 47 K, hole concentration p {approx} 0.08) to overdoped (T{sub c} = 64 K, p {approx} 0.22). We then present quantitative magnetic susceptibility and DC charge transport results that reveal the very high-quality nature of the studied crystals. Using XPS on cleaved samples, we furthermore demonstrate that it is possible to obtain large surfaces of good quality. These characterization measurements demonstrate that Hg1201 should be viewed as a model high-temperature superconductor, and they provide the foundation for extensive future experimental work.« less
  • Nonstoichiometry of (Mg{sub 0.22}Mn{sub 0.07}Fe{sub 0.71}){sub 3{minus}{delta}}O{sub 4} ferrite has been measured in the temperature range of 1,000--1,200 C as a function of oxygen activity (a{sub O{sub 2}}) using a solid state coulometric titration technique. At a given temperature, the nonstoichiometry ({delta}) was found to vary with the oxygen activity as {delta} = [V]{sup 0}{center_dot}a{sub O{sub 2}}{sup 2/3}{minus}[I]{sup 0}{center_dot}a{sub O{sub 2}}{sup {minus}2/3} where [V]{sup 0} and [I]{sup 0} are constants. This a{sub O{sub 2}}-dependence of {delta} was explained in terms of Frenkel disorder, i.e., cation vacancy and interstitial. From the temperature dependence of the defect constants ([V]{sup 0} and [I]{supmore » 0}) and the oxygen activity for the stoichiometric composition ({delta} = 0), thermodynamic quantities such as enthalpies for the defect formation reactions and relative partial molar enthalpy and entropy of oxygen were calculated. 35 refs., 5 figs., 4 tabs.« less
  • We report here the attempted synthesis of (Hg{sub 1{minus}x}Cu{sub y})Ba{sub 2}CuO{sub 4+{delta}} (0{le}x{le}0.2, 0{le}y{le}0.2, y{le}x) and the results of a detailed characterization of the structural and superconducting properties of the resulting samples. Rietveld refinement of powder x-ray-diffraction data collected on all 15 samples synthesized found no partial Cu occupancy of the Hg site. We therefore conclude that for these samples no solid solution exists and the superconducting phase is simply HgBa{sub 2}CuO{sub 4+{delta}}. Only one interstitial oxygen position O(3) was found, located exactly at the center of the Hg plane. An analysis of the structural refinements has produced a numbermore » of correlations between the exact location of the Ba{sup 2+} cation within the unit cell and a number of important superconducting parameters; these include the occupancy of the O(3) site, the extent of oxidation of the CuO{sub 2} planes, and the magnetic penetration depth. {copyright} {ital 1997} {ital The American Physical Society}« less
  • We report a systematic study of the non-stoichiometry and high-temperature transport properties of the perovskite related mixed conductor Sr{sub 3}Fe{sub 2}O{sub 6+{delta}}. The variation of the oxygen content (6+{delta}) with T and equilibrium oxygen partial pressure (pO{sub 2}) was obtained by thermogravimetry within the range: 10{sup -5}<pO{sub 2}<1atm.; 400=<T=<1100 deg. C. From the experimental values of the oxygen chemical potential ({mu}{sub O{sub 2}}), the partial molar enthalpy (h{sub O{sub 2}}) and the partial molar entropy (s{sub O{sub 2}}) were determined for the composition range 6.00<6+{delta}<6.55. A simple defect model based on the mass action law assuming localized charge carriers andmore » oxygen vacancies was used to reproduce the thermodynamic data. Electrical resistivity measurements as a function of pO{sub 2} at constant temperature were obtained within the interval 650=<T=<1000 deg. C. The activation energy values for the electrical transport process at constant oxygen content values were obtained from the combination of electrical conductivity and thermogravimetry data. The electrical transport data are in agreement with the small polaron model.« less