Magnetic ground state of superconducting Eu(Fe0.88Ir0.12)2As2: A combined neutron diffraction and first-principles calculation study

W. T. Jin; Wei Li; Y. Su; S. Nandi; Y. Xiao; W. H. Jiao; M. Meven; A. P. Sazonov; E. Feng; Yan Chen; C. S. Ting; G. H. Cao; Th. Brückel

doi:10.1103/PhysRevB.91.064506

Magnetic ground state of superconducting Eu(Fe0.88Ir0.12)2As2: A combined neutron diffraction and first-principles calculation study

W. T. Jin, Wei Li, Y. Su, S. Nandi, Y. Xiao, W. H. Jiao, M. Meven, A. P. Sazonov, E. Feng, Yan Chen, C. S. Ting, G. H. Cao, Th. Brückel

DOI 10.1103/PhysRevB.91.064506 · Physical Review B

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Abstract

The magnetic order of the localized Eu2+ spins in optimally doped Eu(Fe1−xIrx)2As2 (x=0.12) with superconducting transition temperature TSC=22 K was investigated by single-crystal neutron diffraction. The Eu2+ moments were found to be ferromagnetically aligned along the c direction with an ordered moment of 7.0(1) μB well below the magnetic phase transition temperature TC=17 K. No evidence of the tetragonal-to-orthorhombic structural phase transition was found in this compound within the experimental uncertainty, in which the spin-density-wave (SDW) order of the Fe sublattice is supposed to be completely suppressed and the superconductivity gets fully developed. The ferromagnetic ground state of the Eu2+ spins in Eu(Fe0.88Ir0.12)2As2 was supported by the first-principles density functional calculation. In addition, comparison of the electronic structure calculations between Eu(Fe0.875Ir0.125)2As2 and the parent compound EuFe2As2 indicates stronger hybridization and more expanded bandwidth due to the Ir substitution, which together with the introduction of electrons might work against the Fe-SDW in favor of the superconductivity.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Eu(Fe0.88Ir0.12)2As2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	22	Pressure unresolved	onset
Eu(Fe0.88Ir0.12)2As2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	20.5	Pressure unresolved	zero_resistance
Eu(Fe0.88Ir0.12)2As2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	22	Pressure unresolved	onset
Eu(Fe0.82Co0.18)2As2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	8	Pressure not reported	unknown
EuFe2(As0.85P0.15)2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	25	Pressure not reported	unknown
EuFe2(As0.81P0.19)2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	27	Pressure not reported	unknown
Eu(Fe0.86Ir0.14)2As2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	22.5	Pressure not reported	unknown