"Magnetic order close to superconductivity in the iron-based
layered La0(1-x)F(x)FeAs systems," by Clarina de la Cruz and 10
others, Nature, 7197(453): 899-902, 12 June 2008.
[Authors' affiliations: University of Tennessee, Knoxville; Oak Ridge
National Lab, TN; NIST, Gaithersburg, MD; University of Maryland, College
Park; Ames Lab and Iowa State University; Beijing National Laboratory for
Condensed Matter Physics, China]
Abstract: "Following the discovery of long-range
antiferromagnetic order in the parent compounds of
high-transition-temperature (high-Tc) copper oxides, there have been
efforts to understand the role of magnetism in the superconductivity that
occurs when mobile 'electrons' or 'holes' are doped into the
antiferromagnetic parent compounds. Superconductivity in the newly
discovered rare-earth iron-based oxide systems ROFeAs (R, rare-earth metal)
also arises from either electron or hole doping of their
non-superconducting parent compounds. The parent material LaOFeAs is
metallic but shows anomalies near 150 K in both resistivity and d.c.
magnetic susceptibility. Although optical conductivity and theoretical
calculations suggest that LaOFeAs exhibits a spin-density-wave (SDW)
instability that is suppressed by doping with electrons to induce
superconductivity, there has been no direct evidence of SDW order. Here we
report neutron-scattering experiments that demonstrate that LaOFeAs
undergoes an abrupt structural distortion below 155 K, changing the
symmetry from tetragonal (space group P4/nmm) to monoclinic (space group
P112/n) at low temperatures, and then, at ~137 K, develops long-range
SDW-type antiferromagnetic order with a small moment but simple magnetic
structure. Doping the system with fluorine suppresses both the magnetic
order and the structural distortion in favour of superconductivity.
Therefore, like high-Tc copper oxides, the superconducting regime in these
iron-based materials occurs in close proximity to a long-range-ordered
antiferromagnetic ground state."
This 2008 report from Nature was cited 54
times in current journal articles indexed by Clarivate
during July-August 2009. For what is now the sixth bimonthly period in a
row, this paper scores at #2 among non-review entries in the Hot Papers
"chemistry" category (although, as has been noted previously, this
multidisciplinary report is also recording numerous citations in physics
journals). Prior to the most recent two-month count, citations to the paper
have accrued as follows:
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