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Interplay between magnetism and superconductivity in EuFe 2-x Co x As 2 s tudied by 57 Fe and 151 Eu Mössbauer spectroscopy A. Błachowski 1 , K. Ruebenbauer 1 , J. Żukrowski 2 , Z . Bukowski 3 , K. Rogacki 3 , J. Karpinski 4 1 Mössbauer Spectroscopy Division, Institute of Physics,
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Interplay between magnetism and superconductivity in EuFe2-xCoxAs2 studiedby 57Fe and 151Eu Mössbauer spectroscopy A. Błachowski1, K. Ruebenbauer1, J. Żukrowski2, Z. Bukowski3,K. Rogacki3, J. Karpinski4 1Mössbauer Spectroscopy Division, Institute of Physics, Pedagogical University, Cracow, Poland 2 Solid State Physics Department, Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Cracow, Poland 3 Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wrocław, Poland 4 Laboratory for Solid State Physics, ETH Zürich, Switzerland --------------------------------------------------------------------------------------------------------------------------------------------------------------- XV Krajowa Szkoła Nadprzewodnictwa, Kazimierz Dolny, 9 - 13 października 2011
Fe-based Superconducting Families pnictogens:P, As, Sb chalcogens:S, Se, Te 1111 12211111 LnFeAsO(F)AFe2As2LiFeAs FeTe(Se,S) Ln = La, Ce, Pr, Nd, Sm, Gd … A = Ca, Sr, Ba, Eu Tcmax = 56 K 38 K 18 K 15 K
Layered Structure of Fe-based Superconductors --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Phase Diagram Ba1-xKxFe2As2 BaFe2-xCoxAs2 BaFe2As2-xPx Parent Compounds Doped Compounds ↓ Superconductors
Mössbauer Spectroscopy -ray energy is modulated by the Doppler effect due to the source motion vs. absorber 1 mm/s 48neV
Hyperfine Interactions Isomer Shift Quadrupole Splitting Magnetic Splitting B = 10 T Electron Density Electric Field Gradient Magnetic Hyperfine Field
Electric Field Gradient + Magnetic Hyperfine Field B = 10 T = 0° = 90°
57Fe Mössbauer spectra BaFe2As2 TSDW = 136 K Ba0.7Rb0.3Fe2As2 Tsc = 37 K NM non-magnetic
57Fe Mössbauer spectra CaFe2As2 TSDW = 175 K CaFe1.92Co0.08As2 Tsc = 20 K Relative resistivity (normalized to the resistivity at 300 K) versus temperature
Shape of SDW for various temperatures Square root from the mean squared amplitude of SDW versus temperature
EuFe2As2 Square root from the mean squared amplitude of SDW versus temperature TSDW = 192 K 0 = 0.124 A.Błachowski, K.Ruebenbauer, J.Żukrowski, K.Rogacki, Z.Bukowski, J.Karpinski, PRB 83 134410 (2011)
EuFe2-xCoxAs2 TN (Eu) = 19 K A.Błachowski, K.Ruebenbauer, J.Żukrowski, Z.Bukowski, K.Rogacki, P.J.W.Moll, J.Karpinski, arXiv:1107.5271
EuFe2-xCoxAs2 57Fe Mössbauer spectra TN (Eu) = 19 K TSDW = 190 K TSDW = 150 K TSDW = 100 K traces of SDW at 80 K lack of SDW Eu2+ Transferred Field on 57Fe
EuFe2-xCoxAs2 57Fe Mössbauer spectra Shape ofSDW
EuFe1.66Co0.34As2 Square root from the mean squared amplitude of SDW versus temperature EuFe2-xCoxAs2
EuFe2-xCoxAs2 151Eu Mössbauer spectra
Zakład Spektroskopii Mössbauerowskiej Instytut Fizyki Uniwersytet Pedagogiczny ul. Podchorążych 2, 30-084 Kraków www.elektron.up.krakow.pl/ab