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Title: Hole doping and superconductivity characteristics of the s=1, 2 and 3 members of the (Cu,Mo)-12s2 homologous series of layered copper oxides

Abstract

Superconductivity characteristics have been systematically evaluated for a two-CuO{sub 2}-plane copper oxide system (Cu,Mo)-12s2, upon increasing the number of fluorite-structured layers, s, between the two CuO{sub 2} planes. Essentially single-phase samples of (Cu{sub 0.75}Mo{sub 0.25})Sr{sub 2}YCu{sub 2}O{sub 7+{delta}} (s=1), (Cu{sub 0.75}Mo{sub 0.25})Sr{sub 2}(Ce{sub 0.45}Y{sub 0.55}){sub 2}Cu{sub 2}O{sub 9+{delta}} (s=2) and (Cu{sub 0.75}Mo{sub 0.25})Sr{sub 2}(Ce{sub 0.67}Y{sub 0.33}){sub 3}Cu{sub 2}O{sub 11+{delta}} (s=3) were synthesized through a conventional solid-state route in air. To make the samples superconductive an additional high-pressure oxygenation (HPO) treatment was required. Such treatment (carried out at 5GPa and 500 deg. C in the presence of 75mol% Ag{sub 2}O{sub 2} as an oxygen source to maximize the T{sub c}) compressed the crystal lattice for the three members of the (Cu{sub 0.75}Mo{sub 0.25})-12s2 series equally, i.e., by 0.01A for the a parameter and by 0.07A for the c parameter per formula unit. From both Cu L-edge and O K-edge XANES spectra the s=1 sample was found to possess the highest overall hole-doping level among the HPO samples. Accordingly it exhibited the best superconductivity characteristics. With increasing s, both the T{sub c} (s=1: 88K, s=2: 61K, s=3: 53K) and H{sub irr} values got depressed, being well explained by the trend of decreasingmore » CuO{sub 2}-plane hole concentration with increasing s as revealed from O K-edge XANES spectra for the same samples. Hence, the present results do not suggest any significant (negative) impact on the superconductivity characteristics from the gradually thickened fluorite-structured block itself.« less

Authors:
 [1];  [2];  [2];  [2];  [3];  [4];  [2]
  1. Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan). E-mail: karppinen@msl.titech.ac.jp
  2. Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan)
  3. National Synchrotron Radiation Research Center (NSRRC), Hsinchu, Taiwan (China)
  4. Department of Chemistry, National Taiwan University, Taipei, Taiwan (China)
Publication Date:
OSTI Identifier:
20784785
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 178; Journal Issue: 11; Other Information: DOI: 10.1016/j.jssc.2005.08.029; PII: S0022-4596(05)00385-3; Copyright (c) 2005 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABSORPTION SPECTROSCOPY; COPPER OXIDES; CRYSTAL LATTICES; FLUORITE; LAYERS; SPECTRA; SUPERCONDUCTIVITY; X-RAY SPECTROSCOPY

Citation Formats

Karppinen, M., Morita, Y., Kobayashi, T., Grigoraviciute, I., Chen, J.M., Liu, R.S., and Yamauchi, H. Hole doping and superconductivity characteristics of the s=1, 2 and 3 members of the (Cu,Mo)-12s2 homologous series of layered copper oxides. United States: N. p., 2005. Web. doi:10.1016/j.jssc.2005.08.029.
Karppinen, M., Morita, Y., Kobayashi, T., Grigoraviciute, I., Chen, J.M., Liu, R.S., & Yamauchi, H. Hole doping and superconductivity characteristics of the s=1, 2 and 3 members of the (Cu,Mo)-12s2 homologous series of layered copper oxides. United States. doi:10.1016/j.jssc.2005.08.029.
Karppinen, M., Morita, Y., Kobayashi, T., Grigoraviciute, I., Chen, J.M., Liu, R.S., and Yamauchi, H. Tue . "Hole doping and superconductivity characteristics of the s=1, 2 and 3 members of the (Cu,Mo)-12s2 homologous series of layered copper oxides". United States. doi:10.1016/j.jssc.2005.08.029.
@article{osti_20784785,
title = {Hole doping and superconductivity characteristics of the s=1, 2 and 3 members of the (Cu,Mo)-12s2 homologous series of layered copper oxides},
author = {Karppinen, M. and Morita, Y. and Kobayashi, T. and Grigoraviciute, I. and Chen, J.M. and Liu, R.S. and Yamauchi, H.},
abstractNote = {Superconductivity characteristics have been systematically evaluated for a two-CuO{sub 2}-plane copper oxide system (Cu,Mo)-12s2, upon increasing the number of fluorite-structured layers, s, between the two CuO{sub 2} planes. Essentially single-phase samples of (Cu{sub 0.75}Mo{sub 0.25})Sr{sub 2}YCu{sub 2}O{sub 7+{delta}} (s=1), (Cu{sub 0.75}Mo{sub 0.25})Sr{sub 2}(Ce{sub 0.45}Y{sub 0.55}){sub 2}Cu{sub 2}O{sub 9+{delta}} (s=2) and (Cu{sub 0.75}Mo{sub 0.25})Sr{sub 2}(Ce{sub 0.67}Y{sub 0.33}){sub 3}Cu{sub 2}O{sub 11+{delta}} (s=3) were synthesized through a conventional solid-state route in air. To make the samples superconductive an additional high-pressure oxygenation (HPO) treatment was required. Such treatment (carried out at 5GPa and 500 deg. C in the presence of 75mol% Ag{sub 2}O{sub 2} as an oxygen source to maximize the T{sub c}) compressed the crystal lattice for the three members of the (Cu{sub 0.75}Mo{sub 0.25})-12s2 series equally, i.e., by 0.01A for the a parameter and by 0.07A for the c parameter per formula unit. From both Cu L-edge and O K-edge XANES spectra the s=1 sample was found to possess the highest overall hole-doping level among the HPO samples. Accordingly it exhibited the best superconductivity characteristics. With increasing s, both the T{sub c} (s=1: 88K, s=2: 61K, s=3: 53K) and H{sub irr} values got depressed, being well explained by the trend of decreasing CuO{sub 2}-plane hole concentration with increasing s as revealed from O K-edge XANES spectra for the same samples. Hence, the present results do not suggest any significant (negative) impact on the superconductivity characteristics from the gradually thickened fluorite-structured block itself.},
doi = {10.1016/j.jssc.2005.08.029},
journal = {Journal of Solid State Chemistry},
number = 11,
volume = 178,
place = {United States},
year = {Tue Nov 15 00:00:00 EST 2005},
month = {Tue Nov 15 00:00:00 EST 2005}
}
  • We demonstrate that the T{sub c} value of superconductive copper oxides does not depend on the distance between two adjacent CuO{sub 2} planes as long as the hole-doping level and the immediate (crystal) chemical surroundings of the planes are kept the same. Experimental evidence is accomplished for the homologous series of (Cu,Mo)-12s2, the member phases of which differ from each other by the number (s) of cation layers in the fluorite-structured (Ce,Y)-[O{sub 2}-(Ce,Y)]{sub s-1} block between the CuO{sub 2} planes. X-ray absorption near-edge structure spectroscopy is employed as a probe for the hole states of these phases. The s =more » 1 member appears to be more strongly doped with holes than other phases of the series and accordingly to possess the highest T{sub c} value of 87 K. For s {ge} 2, unexpectedly, both the CuO{sub 2} plane hole concentration and the value of T{sub c} ({approx}55 K) remain constant, being independent of s.« less
  • A detailed study of the structure-property relationship is reported for the first four members of the high-T{sub c} superconducting homologous series of (Cu,Mo)Sr{sub 2}(Ce,Y){sub s}Cu{sub 2}O{sub 5+2s+{delta}} [(Cu,Mo)-12s2]. In this series, the adjacent CuO{sub 2} planes are separated by a single Y-cation layer for s=1 and a fluorite-type (Ce,Y)-[O{sub 2}-(Ce,Y)]{sub s-1} layer block for s {ge} 2. Even though this series may be considered a conventional homologous series from the chemical point of view, we emphasize that the structures are different from those of the Tl-, Hg-, Bi-, etc.,-based series by the fact that the inserted fluorite-type blocks are insulating.more » We show the formation of the higher s members via intercalation of additional Ce-O{sub 2} layer(s) into the crystal lattices of the lower members of the series. Neutron powder-diffraction data demonstrate that the Ce/Y ratio is not constant at the different (Ce,Y) layers in the fluorite-structured block and that the innermost (Ce,Y) layer(s) are significantly Ce rich compared with the outer ones. Two independent crystallographic sites are identified for the extra oxygen atoms in the basal (Cu{sub 0.75}Mo{sub 0.25})O{sub 1+{delta}} plane with site fractional occupancies that strongly correlate with the properties of the material. A short-range ordered structure is proposed for the (Cu{sub 0.75}Mo{sub 0.25})O{sub 1+{delta}} layers that could explain both the superconducting properties of the materials and the enhanced T{sub c} for the first member of the series.« less
  • A newly discovered topological insulator Cm (AgxPb1-xSe)5(Bi2S3)3m (m = 2) has a band gap of 0.5 eV, the largest value reported in topological insulators. We present a magnetotransport study of the Dirac electrons of this compound in the quantum diffusion regime. Two-dimensional weak antilocalization due to the destructive interference of the Dirac electrons was observed. The phase coherence length of the Dirac electrons is independent of doping and disorder levels. This provides an indication of the backscattering immunity under the protection of time reversal invariance of the TI. We further report that the homologous compound (AgxPb1-xSe)5(Bi2S3)3m (m = 1)is amore » superconductor with a transition temperature Tc = 1.7K. The related structures of these two phases allow lateral intergrowth of crystals to occur naturally, offering a potential platform to observe the Majorana fermion state at the boundary of two intergrown crystals.« less
  • We investigate doping- and pressure-induced changes in the electronic state of Mn 3d and As 4p orbitals in II-II-V based diluted magnetic semiconductor (Ba 1-x,K x)(Zn 1-y,Mn y) 2As 2 to shed light into the mechanism of indirect exchange interactions leading to high ferromagnetic ordering temperature (T c = 230 K in optimally doped samples). A suite of x-ray spectroscopy experiments (emission, absorption and dichroism) show that the emergence, and further enhancement of ferromagnetic interactions with increased hole doping into the As 4p band is accompanied by a decrease in local 3d spin density at Mn sites. This is amore » result of increasing Mn 3d - As 4p hybridization with hole doping which enhances indirect exchange interactions between Mn dopants and gives rise to induced magnetic polarization in As 4p states. On the contrary, application of pressure suppresses exchange interactions. While Mn Kβ emission spectra show a weak response of 3d state to pressure, clear As 4p band broadening (hole delocalization) is observed under pressure ultimately leading to loss of ferromagnetism concomitant with a semiconductor to metal transition. The pressure response of As 4p and Mn 3d states is intimately connected with the evolution of the As-As interlayer distance and the geometry of the MnAs 4 tetrahedral units, which we probed with X-ray diffraction. Our results indicate that hole doping increases the degree of covalency between the anion (As) p states and cation (Mn) d states in the MnA s4 tetrahedron, a crucial ingredient to promote indirect exchange interactions between Mn dopants and high T c ferromagnetism. As a result, the instability of ferromagnetism and semiconducting state against pressure is mainly dictated by delocalization of anion p states.« less