A new family of quaternary iron-based superconductors with superconducting transition temperatures (T_c) up to 52 K are discussed in the latest issue of Physics Today.  The family of compounds, based on LaOFeAs (so called 1:1:1:1 phase), was first synthesized by Jeitschko at Dupont in the mid-1970s and more recent work by HIdeo Hosono at the Tokyo Institute of Technology.  The current record T_c~52 K was reported by Zhongxian Zhao of the Insitute of Physics in Beijing.

These new materials may be of some interest for thermoelectrics.  Conduction is said to be two-dimensional in the FeAs planes.   The low dimension and the transition metal (Fe) may both favor high Seebeck coefficients.  Of particular interest would be Hall effect, Seebeck and thermal conductivity so that the beta value and potential for high ZT might be estimated.  Someone is sure to report ZT values soon (if it has not already happened).