'Single-Crystal' Superconductors are a Big Step for the Field

(PhysOrg.com) -- In key advances for the field of superconductivity, a research group has created versions of a class of widely studied superconducting compounds that are each one continuous crystal, rather than composed of many crystalline grains. These single-crystal materials are important achievements because they display better properties than polycrystalline types and are easier to study.

In a series of four recent papers, three published in Physical Review B and one in Physical Review Letters, the researchers describe the process they developed to "grow" the single-crystal materials.

The group, which includes scientists from Ames Laboratory in Iowa, Iowa State University (ISU), and San Diego State University, created single-crystal versions of two iron arsenide superconductors, a class of superconductors currently being examined by researchers across the globe. However, most of these researchers are studying polycrystalline varieties, with only recent work coming out on single crystals.

The first paper1 describes the barium/iron/arsenic superconductor BaFe2As2 and a compound derived from it that contains a slightly different amount of barium as well as small amounts of potassium.

Source: http://www.physorg.com/news139139958.html

Image caption:
A sample of a potassium-doped iron arsenide superconductor, shown on a millimeter grid. Image courtesy the American Physical Society [N. Ni et al. (10 July 2008). Anisotropic thermodynamic and transport properties of single-crystalline Ba1－xKxFe2As2 (x=0 and 0.45). Physical Review B, Vol 78, p014507, Fig 1]