Polarized neutron diffraction study of the field-induced magnetization in the normal and superconducting states of Ba(Fe1−xCox)

C. Lester

¹

,

Jiun‐Haw Chu

²

,

James Analytis

³

et al.

Spin susceptibility in superconducting LiFeAs studied by polarized neutron diffraction

“…1 agree perfectly with those obtained by the same flipping-ratio technique for Co-doped BaFe 2 As 2 [35]. Both the magnetization in the normal phase and the suppression of susceptibility in the superconducting state are comparable in both compounds, which disagrees with speculations that stoichiometric LiFeAs is very close to a ferromagnetic instability.…”

“…However, the spin susceptibility does not fully disappear at low temperatures. This behavior occurs also in other superconductors like V 3 Si and Ba(Fe 1−x Co x ) 2 As 2 (x = 0.065) [26,28,35]. The origins of this residual value are the van Vleck part of the susceptibility [43] and the spin susceptibility in the vortex cores arising from the high field of our measurement, χ res .…”

“…This experiment was interpreted as evidence of an odd-wave spin-triplet pairing. In other FeAs-based superconductors Knight-shift experiments [31][32][33][34] indicate singlet pairing, as well as a polarized neutron-diffraction study on Co-doped BaFe 2 As 2 [35].…”

Magnetization distribution and orbital moment in the nonsuperconducting chalcogenide compound K0.8Fe1.6SeNandi1, Xiao2, Su3 et al. 2013Phys. Rev. B2000View full textAdd to dashboardCite

“…The magnetic structure factors calculated for this constrained multipole model are given together with the measured values and the diamagnetic corrections in Table II. There have been a few reports of magnetization distribution for the superconducting and nonsuperconducting Fe based compounds. 21,34,[36][37][38] Of particular interest are the results of BaFe 2 As 2 by Brown et al 34 who have shown that most of the magnetization is associated with the Fe atoms and the distribution is nonspherical with an extension along the 1 1 1 direction. For the superconducting Ba(Fe 1−x Co x ) 2 As 2 samples both Prokeš et al 36 and Lester et al 21 have concluded that the magnetization is rather extended along the 1 1 0 direction.…”

“…21,34,[36][37][38] Of particular interest are the results of BaFe 2 As 2 by Brown et al 34 who have shown that most of the magnetization is associated with the Fe atoms and the distribution is nonspherical with an extension along the 1 1 1 direction. For the superconducting Ba(Fe 1−x Co x ) 2 As 2 samples both Prokeš et al 36 and Lester et al 21 have concluded that the magnetization is rather extended along the 1 1 0 direction. The change in distribution between the doped and undoped samples is due to the doping induced modifications of the relevant bands near the Fermi surface as suggested by Lester et al 21 In contrast to all of the investigated Fe pnictides, K 0.8 Fe 1.6 Se 2 shows distribution elongated along the 0 0 1 direction.…”