May 10, 2010 (HP30). We attract the attention of our readers to the May 2010 Issue ofSuperconductor Science and Technology (SuST), which includes a special section “Focus on the electromagnetic properties of iron-based superconductors”. This special section is guest-edited by Ruslan Prozorov from Iowa State Univ. (US), Alex Gurevich from the National High Magnetic Field Laboratory (US) and Graeme Luke from McMaster Univ. (Canada). We cite the introductory part of their editorial article:
“Iron-based superconductors, discovered just a few years ago, are members of a
diverse family of pnictides and chalcogenides which may potentially contain
hundreds of superconducting compounds. The unconventional, multiband
superconductivity in these materials most likely emerges from the quintessential
magnetic Fe ions. Along with many similarities to the high-Tc cuprates, the
proximity of antiferromagnetism to superconductivity in these semi-metallic
materials has attracted much attention. The massive effort aimed at understanding
superconductivity in the high-Tc cuprates has stimulated the development of
numerous state-of-the-art experimental techniques, improved crystal growth
methods and a variety of new theoretical insights. These tools and models were
already available and readily applied to the new iron-based superconductors for
which lots of high quality new results are being reported literally every day. The
current special section represents only a snapshot of these extensive studies
performed in the second half of 2009, less than two years after the discovery of
26 K superconductivity in the LaFeAsO compound. The range of various
experiments is impressive and this issue is mostly focused on the electromagnetic
properties of these iron-based materials. The electromagnetic response is
sensitive to the microscopic electronic behavior and therefore can be used to
probe the mechanism of superconductivity. On the other hand, it is the
electromagnetic response that determines many possible applications of these
superconductors, particularly given their extremely high upper critical fields. At
this point it is already quite clear that the iron-based superconductors cannot
unambiguously fit into any known type of superconductor class and have been
placed in one of their own. The metallic ground state of the parent compounds is
different from the insulating state of the cuprates and generally exhibits a lower
electromagnetic anisotropy. However, similar to the cuprates, a superconducting
‘dome’ is formed upon doping the parent compounds, which exhibits
antiferromagnetic and structural transitions at temperatures well above the
superconducting critical temperature."
The special section touches on several key aspects of these new iron-based superconductors including materials synthesis and basic characterization, the role of impurities and pairing symmetry, and mapping of the superconducting phase diagram. Studies of transport, magnetic and optical properties account for a substantial portion of this special section.
Important for those, who don’t subscribe to SuST: Until the end of 2010, full texts of all articles of the Special Section highlighted here are accessible free-of-charge at:http://iopscience.iop.org/0953-2048/23/5.