Browsing by Author "Hamelo, Shewangizaw"

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    Iron Pnictide Super conductors
    (Addis Ababa University, 2011-06) Hamelo, Shewangizaw
    The discovery of new superconductor LaFeAsOi􀀀xFx with a superconducting critical temprature, Tc of 26K in 2008 has quickly renewed interest in the exploration of iron- based superconductors. More new superconductors have been discovered with the highest Tc of up to 55K being observed in the SmFeAsO1􀀀xFx compound. High Tc have previosly only been observed in cuprates, these new iron based superconductors have been added as second member of high Tc family. The crystal structur of these compound contains an almoost 2D Fe-As layer formed by FeAS4 tetrahedrons,which can be separeted an ionic layer that provides an extra electron to Fe-As layer superconductivity can be induced by carrier doping,which destroy the antifrromagnetic ground state. The pairing mechanisim has been clari ed as unconventional and antiferromagnetic(AF) spin uctuations (SFs) seem to play an important role in making these pairs. In this paper superconducting crystal structur, physical properties of parent compounds, pressure e ects, the electronic state of the compounds will be presented