Book of Abstracts From Spins to Cooper Pairs and Back: 2nd

Book of Abstracts
From Spins to Cooper Pairs and Back:
2nd International Conference on
Magnetism and Superconductivity
in Selected Systems
September 25-30, 2016
Zakopane
Local organizing committee
Jagiellonian University
Józef Spałek (chairman)
Danuta Goc-Jagło (secretary)
Andrzej Kapanowski
Adam Rycerz
Marcin Abram
Maciej Fidrysiak
Andrzej Kądzielawa
Ewa Kądzielawa-Major
Adam Kłosiński
Grzegorz Rut
AGH University of Science and Technology
Zbigniew Kąkol
Andrzej Biborski
Michał Zegrodnik
Cracow Uniwersity of Technology
Włodzimierz Wójcik
ii
StoCP-2016 Conference – Posters
65
Influence of doping on charge modulation at superconducting transition in iron pnictides studied by Mössbauer spectroscopy
A. Błachowski1 , A. K. Jasek1 , A. Pierzga1 , K. Komędera1 , K. Ruebenbauer1 ,
Z. Bukowski2 , and K. Rogacki2
1
Mössbauer Spectroscopy Laboratory, Pedagogical University, 30-084 Kraków, Podchorążych 2,
Poland
2 Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422
Wrocław, ul. Okólna 2, Poland
Iron-based superconductors Ba0.6 K0.4 F e2 As2 belonging to ’122’ family (critical
temperature Tc = 38K) and SmF eAsO0.91 F0.09 belonging to ’1111’ family (Tc =
47K) were investigated by Mössbauer spectroscopy versus temperature with particular
attention paid to the region of superconducting transition. Spectra display quasicontinuous distribution of quadrupole doublets in the whole temperature range. A
distribution is caused by the spatial modulation of the electric field gradient, i.e., by the
electric field gradient wave (EFGW), the latter being consequence of the incommensurate
modulation of the charge density on the iron nuclei, i.e., the charge density wave (CDW).
Shape and amplitude of EFGW and CDW are strongly perturbed at the superconducting
transition. Namely, all modulations are strongly changed at critical temperature due to
the superconducting gap opening and subsequent formation of Cooper pairs. However
dispersion of the charge density and EFGW shape behave in the opposite ways for these
two superconductors. These differences follow the manner of doping above compounds
to achieve superconductivity. The ’122’ superconductor is hole doped, while the ’1111’
superconductor is electron doped. Hence, the Fermi surface moves opposite way for
above cases.