Structural inhomogeneities in Fe Te0.6Se0.4: Relation to superconductivity

Autor: Prokes, K., Schulze, M., Hartwig, S., Schaefer, N., Landsgesell, S., Blum, C. G. F., Abou-Ras, D., Hacisalihoglu, M. Y., Ressouche, Eric, Ouladdiaf, D. B., Buechner, B., Wurmehl, S.
Přispěvatelé: Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), Leibniz Institute for Solid State and Materials Research (IFW Dresden), Leibniz Association, Magnétisme et Diffusion Neutronique (MDN), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut Laue-Langevin (ILL), ILL, Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Jazyk: angličtina
Rok vydání: 2015
Předmět:
Zdroj: Journal of Crystal Growth
Journal of Crystal Growth, Elsevier, 2015, 432, pp.95-104. ⟨10.1016/j.jcrysgro.2015.09.014⟩
Journal of Crystal Growth, 2015, 432, pp.95-104. ⟨10.1016/j.jcrysgro.2015.09.014⟩
ISSN: 0022-0248
Popis: International audience; Chemical and structural phase compositions of two single-crystalline samples prepared with different cooling rates from stoichiometric FeTe0.6Se0.4 melts were studied. Both types of samples were investigated in a very comprehensive way using magnetic and electrical transport measurements combined with X-ray, neutron and electron backscatter diffraction. We show that slowly cooled samples are homogeneous on a microscopic scale with only a small excess of iron. Those slowly cooled samples do not exhibit bulk superconductivity down to 1.8 K. In contrast, fast-cooled samples are superconducting below about 14 K but are composed of several chemical phases: they consist of a matrix preserving the crystal structure of slow-cooled samples, and of core-shell structured dendritic inclusions (about 2030 vol%). These have different crystal structures and chemical compositions and order magnetically at temperatures far above the superconducting transition temperature of the inhomogeneous samples. These structural and chemical inhomogeneities seem to play a vital role in the superconducting properties of this and similar iron-based systems as they lead to internal stress and act in a similar way as the application of the external pressure that reportedly increase the superconducting transition temperature in many iron pnictides and chalcogenides. We argue that a phase pure, homogeneous and stress-free FeTe0.6Se0.4 is non-superconducting. (C) 2015 Elsevier B.V. All rights reserved.
Databáze: OpenAIRE
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