[institut] Podsecanje na seminar Centra za fiziku cvrstog stanja i nove materijale

[Zoran Popovic]

  Postovane koleginice i kolege,
  Danas, u cetvrtak 14.06 u 12 casova u citaonici IF u okviru seminara 
Centra
  za fiziku cvrstog stanja i nove materijale

  dr Cedomir Petrovic,
  Condensed Matter Physics,
  Brookhaven National Laboratory

  odrzace seminar sa temom

  Stoichiometry and Superconductivity in Fe Chalcogenides

  Rezime
  I will outline some recent developments in iron based chalcogenide
  superconductors. Selected single crystal thermodynamic, transport and
  magnetic characterization results will be presented as well as their
  connection with stoichiometry and other key structural parameters that
  have significant influence on magnetic and superconducting states.
  Physical properties of binary Fe based superconductors will be focused
  on upper critical field behavior in high magnetic fieds [1-3]. Single
  crystal alloys KxFe2-ySe2-zSz offer valuable insight into the strength
  of electronic correlations in the normal state and structural
  characteristics associated with superconductivity. I will discuss the
  evolution of the superconducting and magnetic ground states as a
  function of sulfur concentration z and some noticeable changes in the
  average and local crystal structure associated with this [4-7]. The
  superconductivity persists with relatively high Tc even when
  electronic correlations in the normal state are greatly reduced. The
  results for z = 0 will be compared with other experimental techniques
  that probe nanoscale phase separation and degree of vacancy order
  [8-9]. It will be shown that local structure and population of
  particular Fe sites is rather important for obtaining the bulk
  superconducting phase. Superconducting volume fraction and homogeneity
  of superconducting phase is in direct competition with Fe vacancy
  order [10]. References: [1] Phys. Rev. B 81, 094518 (2010), [2] Phys.
  Rev. B 81, 184522 (2010), [3] Europhys. Lett. 95, 57006 (2011), [4]
  Phys. Rev. Lett. 107, 137002 (2011) [5] Phys. Rev. B 83, 180503 (2011)
  [6] Phys. Rev. B 174503 (2011) [7] Phys. Rev. B 84, 054526 (2011) [8]
  Phys. Rev. B 83, 140505 (2011) [9] arXiv:1104.4941 (2011) [10]
  arXiv:1111.2597.

  Srdacan pozdrav
  Zoran