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arXiv · 1103.0059

57-Fe Mossbauer study of magnetic ordering in superconducting K_0.85Fe_1.83Se_2.09 single crystals

D. H. Ryan·W. N. Rowan-Weetaluktuk·J. M. Cadogan·R. Hu·W. E. Straszheim·S. L. Bud'ko·P. C. Canfield
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Abstract

The magnetic ordering of superconducting single crystals of K_0.85Fe_1.83Se_2.09 has been studied between 10K and 550K using 57-Fe Mossbauer spectroscopy. Despite being superconducting below T_sc ~30K, the iron sublattice in K_0.85Fe_1.83Se_2.09 clearly exhibits magnetic order from well below T_sc to its N\'eel temperature of T_N = 532 +/- 2K. The iron moments are ordered perpendicular to the single crystal plates, i.e. parallel to the crystal c-axis. The order collapses rapidly above 500K and the accompanying growth of a paramagnetic component suggests that the magnetic transition may be first order, which may explain the unusual temperature dependence reported in recent neutron diffraction studies.

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D. H. Ryan, W. N. Rowan-Weetaluktuk, J. M. Cadogan, R. Hu, W. E. Straszheim, S. L. Bud'ko, P. C. Canfield. 2011-03-01. 57-Fe Mossbauer study of magnetic ordering in superconducting K_0.85Fe_1.83Se_2.09 single crystals. https://doi.org/10.1103/physrevb.83.104526

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