Regensburg 2013 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 39: Focused Session: Magnetism & Superconductivity in Fe-based Pnictides and Chalcogenides (jointly with MA)
MA 39.7: Vortrag
Donnerstag, 14. März 2013, 12:30–12:45, H20
Growth and characterization of Rb1−xFe2−ySe2 single crystals — •Vladimir Tsurkan1,2, Joachim Deisenhofer1, Axel Günther1, Hans-Albrecht Krug von Nidda1, Sebastian Widmann1, and Alois Loidl1 — 1Experimental Physics 5, Center for Electronic Correlations and Magnetism, University of Augsburg, D 86159, Augsburg, Germany — 2Institute of Applied Physics, Academy of Sciences of Moldova, MD-2028, Chisinau, R. Moldova
Growth of single crystals of Rb-Fe-Se system and their characterization by X-ray powder diffraction, Squid magnetometry, conductivity, and specific heat are presented [1]. The single crystals exhibit an anisotropic antiferromagnetism below 400 K. For 1.53 < Fe < 1.6 the superconducting (SC) behavior is found. The sharp transition into the SC state at 32.4 K is observed for Rb0.8Fe1.6Se2. For the Fe concentrations below 1.5 and above 1.6, respectively, samples show insulating and semiconducting behavior. Magnetic behavior of SC and non-SC samples provides an evidence for the coexistence of superconductivity and static antiferromagnetic order. The evolution of the SC and AFM correlations in the Rb-Fe-Se system is discussed within the constructed phase diagram which includes several structural phases with different magnetic behavior. The coexistence of the superconductivity and antiferromagnetism in Rb0.8Fe1.6Se2 is considered within a scenario of phase separation based on the results of neutron scattering, Mössbauer spectroscopy, optical, µSR, and nuclear magnetic resonance investigations.
[1] V. Tsurkan, J. Deisenhofer, A. Günther, H.-A. Krug von Nidda, S. Widmann, and A. Loidl, Phys. Rev. B 84, 144520 (2011)