"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
Condesed 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 62
times in current journal articles indexed by Clarivate
during November-December 2008. For the second consecutive bimonthly period,
this paper emerges at #2 in the Hot Papers "chemistry" category (although,
as was noted last time, this interdisciplinary report is also attracting
citations in physics journals). Prior to the most recent two-month tally,
citations to the paper have accrued as follows:
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