Journal Article

FZJ-2016-06960

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Phase diagram of Eu magnetic ordering in Sn-flux-grown Eu ( Fe 1 − x Co x ) 2 As 2 single crystals

Jin, W. (Corresponding author)FZJ* ; Xiao, Y. ; Bukowski, Z. ; Su, Y.FZJ* ; Nandi, S. ; Sazonov, A. P. ; Meven, M.FZJ* ; Zaharko, O. ; Demirdis, S.FZJ* ; Nemkovskiy, K.FZJ* ; Schmalzl, K.FZJ* ; Tran, L. M. ; Guguchia, Z. ; Feng, E.FZJ* ; Fu, Z.FZJ* ; Brückel, T.FZJ*

2016
Inst. Woodbury, NY

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Please use a persistent id in citations: http://hdl.handle.net/2128/13075  doi:10.1103/PhysRevB.94.184513

Abstract: The magnetic ground state of the Eu2+ moments in a series of Eu(Fe1−xCox)2As2 single crystals grown from the Sn flux has been investigated in detail by neutron diffraction measurements. Combined with the results from the macroscopic properties (resistivity, magnetic susceptibility and specific heat) measurements, a phase diagram describing how the Eu magnetic order evolves with Co doping in Eu(Fe1−xCox)2As2 is established. The ground-state magnetic structure of the Eu2+ spins is found to develop from the A-type antiferromagnetic (AFM) order in the parent compound, via the A-type canted AFM structure with some net ferromagnetic (FM) moment component along the crystallographic c direction at intermediate Co doping levels, finally to the pure FM order at relatively high Co doping levels. The ordering temperature of Eu declines linearly at first, reaches the minimum value of 16.5(2) K around x=0.100(4), and then reverses upwards with further Co doping. The doping-induced modification of the indirect Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction between the Eu2+ moments, which is mediated by the conduction d electrons on the (Fe,Co)As layers, as well as the change of the strength of the direct interaction between the Eu2+ and Fe2+ moments, might be responsible for the change of the magnetic ground state and the ordering temperature of the Eu sublattice. In addition, for Eu(Fe1−xCox)2As2 single crystals with 0.10≤x≤0.18, strong ferromagnetism from the Eu sublattice is well developed in the superconducting state, where a spontaneous vortex state is expected to account for the compromise between the two competing phenomena.

Keyword(s): Basic research (1st) ; Condensed Matter Physics (2nd) ; Magnetism (2nd)

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Contributing Institute(s):

1. JCNS-FRM-II (JCNS (München) ; Jülich Centre for Neutron Science JCNS (München) ; JCNS-FRM-II)
2. Streumethoden (JCNS-2)
3. Streumethoden (PGI-4)
4. JARA-FIT (JARA-FIT)

Research Program(s):

1. 524 - Controlling Collective States (POF3-524) (POF3-524)
2. 6212 - Quantum Condensed Matter: Magnetism, Superconductivity (POF3-621) (POF3-621)
3. 6G15 - FRM II / MLZ (POF3-6G15) (POF3-6G15)
4. 6G4 - Jülich Centre for Neutron Research (JCNS) (POF3-623) (POF3-623)

Experiment(s):

1. HEiDi: Single crystal diffractometer on hot source (SR9b)
2. DNS: Diffuse scattering neutron time of flight spectrometer (NL6S)

Appears in the scientific report 2016

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Database coverage:
; ; ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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