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Title: Resonance in Optimally Electron-Doped Superconductor Nd 1.85Ce 0.15CuO 4−?

Abstract

We use inelastic neutron scattering to probe magnetic excitations of an optimally electron-doped superconductor Nd1.85Ce0.15CuO4− above and below its superconducting transition temperature Tc = 25 K. In addition to gradually opening a spin pseudo gap at the antiferromagnetic ordering wavevector Q = (1/2, 1/2, 0), the effect of superconductivity is to form a resonance centered also at Q = (1/2, 1/2, 0) but at energies above the spin pseudo gap. The intensity of the resonance develops like a superconducting order parameter, similar to those for hole-doped superconductors and electron-doped Pr0.88LaCe0.12CuO4. The resonance is therefore a general phenomenon of cuprate superconductors, and must be fundamental to the mechanism of high-Tc superconductivity.

Authors:
 [1];  [1];  [2];  [3];  [4];  [5]
  1. ORNL
  2. University of Tennessee, Knoxville (UTK)
  3. Institut Laue-Langevin (ILL)
  4. Spin Superstructure Project, ERATO, Japan Science and Technology, Tsukuba 305-85
  5. University of Tokyo, Tokyo, Japan
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); High Flux Isotope Reactor
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
958781
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 99
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CERIUM OXIDES; COPPER OXIDES; CUPRATES; MESONS; NEODYMIUM OXIDES; NEUTRONS; ORDER PARAMETERS; RESONANCE; SCATTERING; SPIN; SUPERCONDUCTIVITY; SUPERCONDUCTORS; TRANSITION TEMPERATURE; Resonance; Electron-Doped; Nd1.85Ce0.15CuO4−

Citation Formats

Zhao, Jun, Dai, Pengcheng, Li, Shiliang, Freeman, Paul G., Onose, Y,., and Tokura, Y. Resonance in Optimally Electron-Doped Superconductor Nd1.85Ce0.15CuO4−?. United States: N. p., 2007. Web. doi:10.1103/PhysRevLett.99.017001.
Zhao, Jun, Dai, Pengcheng, Li, Shiliang, Freeman, Paul G., Onose, Y,., & Tokura, Y. Resonance in Optimally Electron-Doped Superconductor Nd1.85Ce0.15CuO4−?. United States. doi:10.1103/PhysRevLett.99.017001.
Zhao, Jun, Dai, Pengcheng, Li, Shiliang, Freeman, Paul G., Onose, Y,., and Tokura, Y. Mon . "Resonance in Optimally Electron-Doped Superconductor Nd1.85Ce0.15CuO4−?". United States. doi:10.1103/PhysRevLett.99.017001.
@article{osti_958781,
title = {Resonance in Optimally Electron-Doped Superconductor Nd1.85Ce0.15CuO4−?},
author = {Zhao, Jun and Dai, Pengcheng and Li, Shiliang and Freeman, Paul G. and Onose, Y,. and Tokura, Y.},
abstractNote = {We use inelastic neutron scattering to probe magnetic excitations of an optimally electron-doped superconductor Nd1.85Ce0.15CuO4− above and below its superconducting transition temperature Tc = 25 K. In addition to gradually opening a spin pseudo gap at the antiferromagnetic ordering wavevector Q = (1/2, 1/2, 0), the effect of superconductivity is to form a resonance centered also at Q = (1/2, 1/2, 0) but at energies above the spin pseudo gap. The intensity of the resonance develops like a superconducting order parameter, similar to those for hole-doped superconductors and electron-doped Pr0.88LaCe0.12CuO4. The resonance is therefore a general phenomenon of cuprate superconductors, and must be fundamental to the mechanism of high-Tc superconductivity.},
doi = {10.1103/PhysRevLett.99.017001},
journal = {Physical Review Letters},
number = ,
volume = 99,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • We use inelastic neutron scattering to probe magnetic excitations of an optimally electron-doped superconductor Nd{sub 1.85}Ce{sub 0.15}CuO{sub 4-{delta}} above and below its superconducting transition temperature T{sub c}=25 K. In addition to gradually opening a spin pseudogap at the antiferromagnetic ordering wave vector Q=(1/2,1/2,0), the effect of superconductivity is to form a resonance centered also at Q=(1/2,1/2,0) but at energies above the spin pseudogap. The intensity of the resonance develops like a superconducting order parameter, similar to those for hole-doped superconductors and electron-doped Pr{sub 0.88}LaCe{sub 0.12}CuO{sub 4}. The resonance is therefore a general phenomenon of cuprate superconductors, and must be fundamentalmore » to the mechanism of high-T{sub c} superconductivity.« less
  • We report measurements of the magnetoresistance of Nd{sub 1.85}Ce{sub 0.15}CuO{sub 4{plus_minus}{delta}} epitaxial thin films with varying oxygen content in magnetic fields {ital H} applied parallel ({ital H}{parallel}{ital c}) and perpendicular ({ital H}{perpendicular}{ital c}) to the tetragonal {ital c} axis. We have observed critical scaling of the electrical resistivity that is consistent with a vortex-glass transition for a film with an optimum superconducting transition temperature {ital T}{sub {ital c}} of {approx_equal}22 K and {ital H}{parallel}{ital c}. The values of the zero-temperature upper critical field {ital H}{sub {ital c}{sub 2}}(0)=80 kOe and the in-plane zero-temperature coherence length {xi}{sub {ital ab}}(0)=64 A weremore » obtained from an analysis of the fluctuation conductivity. For an overoxygenated film with {ital T}{sub {ital c}}{approx_equal}10 K, an anomaly develops with increasing field for {ital H}{parallel}{ital c} and {ital T}{approx_lt}2 K that is characterized by a minimum in the temperature dependence of the resistivity followed by a second resistive transition at a lower temperature, which is nearly independent of {ital H}. This behavior is similar to that previously observed in Nd{sub 2{minus}{ital x}}Ce{sub {ital x}}CuO{sub 4{minus}{delta}} single crystals and may be associated with the magnetic ordering of the Nd{sup 3+} ions. {copyright} {ital 1996 The American Physical Society.}« less
  • A single phase polycrystalline sample of Nd{sub 1.85}Ce{sub 0.15}CuO{sub 4} has been synthesized and well characterized. Detailed studies on electrical resistivity behavior of this system as a function of temperature and magnetic field reveal interesting features attributable to the granularity effects. These features have been qualitatively understood based on the interplay of Josephson junction coupling and quasi particle tunneling which dictates the evolution of the observed temperature and field dependent resistivity behavior of Nd{sub 1.85}Ce{sub 0.15}CuO{sub 4} system. The studies also reveal significant changes with respect to annealing conditions, indicating that such compounds are very sensitive to annealing conditions. Itmore » has been observed that prolonged annealing in Argon atmosphere leads to a decrease in normal state resistivity. This is associated with a decrease in the S-I-S type Josephson tunnel junctions perhaps due to improved inter-granular coupling, nevertheless they could not be completely eliminated.« less
  • Normal and superconducting Nd{sub 2{minus}x}Ce{sub x}CuO{sub 4{minus}y} (x = 0.00, 0.15) compounds have been studied by electron spin resonance (ESR). In contrast to previous reports that the high-temperature superconducting oxocuprate compounds are ESR silent, a conduction ESR (CESR) signal has been observed in the superconducting Nd{sub 1.85}Ce{sub 0.15}CuO{sub 4{minus}y} compound. The temperature dependence of the CESR signal intensity, g value, and line width are consistent with a two-dimensional spin structure in Nd{sub 1.85}Ce{sub 0.15}CuO{sub 4{minus}y}. A possible reason for the lack of a CESR signal in other high-temperature superconducting systems is that they have more efficient spin-lattice relaxation which ismore » associated with CESR lines too broad to be detected. 14 refs., 4 figs.« less
  • No abstract prepared.