[institut] seminar Centra

[Zoran Popovic]

Postovane koleginice i kolege,
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
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.ipb.ac.rs/pipermail/institut/attachments/20120611/291b68f0/attachment.htm>