May 23, 2008 (H25). A group of Chinese authors reported in the latest paper published inSuperconductor Science and Technology (SuST) on the recently discovered FeAs-based superconducting compounds.

“Superconductivity at 53.5 K in GdFeAsO_(1-δ)” by Z-A Ren et al. reports the fabrication and superconductivity of the iron-based arsenic-oxideGdFeAsO_(1-δ) compound with oxygen-deficiency, which has an onset resistivity transition temperature of 53.5 K.  This material has the same crystal structure as the high-T_c ReFeAsO_1−δ family (Re = rare earth metal) newly discovered by Kamihara et al^[1].  TheGdFeAsO_(1-δ) has a further reduced crystal lattice, while the T_c is lower than in the SmFeAsO_1−δsystem. 

As a rapid communication, this SuST paper is permanently free for everyone to read at http://www.iop.org/EJ/toc/0953-2048/21/8

Fig. 1.  The temperature dependence of the dc susceptibility and the differential ZFC curve for the nominal GdFeAsO_0.85 sample synthesized by the high-pressure synthesis (HP) method.