1 Magnetyzm i nadprzewodnictwo w EuFe2-xCoxAs2 – badania metodą spektroskopii mössbauerowskiej 57Fe i 151Eu A. Błachowski1, K. Ruebenbauer1, J. Żukrowski2, Z. Bukowski3, K. Rogacki3, P.J.W. Moll4, J. Karpinski4, M. Matusiak3 1Laboratorium Spektroskopii Mössbauerowskiej, Uniwersytet Pedagogiczny, Kraków, Polska 2Katedra Fizyki Ciała Stałego, Wydział Fizyki i Informatyki Stosowanej, Akademia Górniczo-Hutnicza, Kraków, Polska 3Instytut Niskich Temperatur i Badań Strukturalnych PAN, Wrocław, Polska 4Laboratory for Solid State Physics, ETH Zurich, Switzerland IX Ogólnopolskie Seminarium Spektroskopii Mössbauerowskiej OSSM’2012, Lublin - Kazimierz Dolny, czerwca 2012

2 Fe-based Superconducting Familiespnictogens: P, As, Sb chalcogens: S, Se, Te LnFeAsO(F) AFe2As LiFeAs FeTe(Se,S) Ln = La, Ce, Pr, Nd, Sm, Gd … A = Ca, Sr, Ba, Eu Tc max = 56 K K K K

3 Layered Structure of Fe-based Superconductors Phase Diagram Ba1-xKxFe2As2 BaFe2-xCoxAs2 BaFe2As2-xPx Parent Compounds Doped Compounds ↓ Superconductors

4 ”122” family of Fe-based superconductors

5 (normalized to the resistivity at 300 K)57Fe Mössbauer spectra CaFe2As2 TSDW = 175 K CaFe1.92Co0.08As2 Tsc = 20 K Relative resistivity (normalized to the resistivity at 300 K) versus temperature A.Błachowski, K.Ruebenbauer, J.Żukrowski, Z.Bukowski, M.Matusiak, J.Karpinski, Acta Physica Polonica A 121, 726 (2012)

6 57Fe Mössbauer spectra Ba0.7Rb0.3Fe2As2 Tsc = 37 K BaFe2As2TSDW = 136 K Ba0.7Rb0.3Fe2As2 Tsc = 37 K NM non-magnetic

7 Shape of SDW for various temperaturesSquare root from the mean squared amplitude of SDW versus temperature

8 Square root from the mean squared amplitude of SDWEuFe2As2 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, Phys. Rev. B 83, (2011)

9 EuFe2-xCoxAs2 TN (Eu) = 19 K Phys. Rev. B 84, 174503 (2011)A.Błachowski, K.Ruebenbauer, J.Żukrowski, Z.Bukowski, K.Rogacki, P.J.W.Moll, J.Karpinski, Phys. Rev. B 84, (2011)

10 EuFe2-xCoxAs2 57Fe Mössbauer spectra Eu2+ Transferred Field on 57FeTN (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

11 EuFe2-xCoxAs2 57Fe Mössbauer spectra Shape of SDW

12 Square root from the mean squared amplitude of SDWEuFe1.66Co0.34As2 Square root from the mean squared amplitude of SDW versus temperature EuFe2-xCoxAs2

13 151Eu Mössbauer spectroscopy

14 EuFe2-xCoxAs2 151Eu Mössbauer spectra

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