Competing Ferromagnetism and Superconductivity on FeAs Layers inEuFe2(As0.73P0.27)2

Abstract

We have measured the spin-polarized electron momentum density distributions of EuFe2(As0.73P0.27)2 by magnetic Compton scattering (MCS) measurements. For the first time, we show direct evidence of competing ferromagnetism and superconductivity (SC) on FeAs layers in this iron pnictide system. The MCS orbitalwise decomposition of the density distributions reveals that between 16 and 19 K, the spin-polarized Fe-3d character is enhanced (as the ferromagnetic character supersedes superconducting character), where the resistivity shows a maximum, reentrant SC-like peak, at 18 K. The spin polarization of the Fe-3d orbital, enhanced by ferromagnetic Eu ions, suppresses the SC around 18 K, while at other temperatures the system indeed exhibits SC where the Fe-3d spin polarization is suppressed or collapses.

Coexistence of ferromagnetism and superconductivity inCeO0.3F0.7BiS2

“…The spin Hamiltonian most applicable to our system suggests that the inter-layer coupling is negligible. This may indicate that the coexistence of ferromagnetism and superconductivity is made possible by the electronic separation of the superconducting layer and the magnetic layer, for instance, as in the case of EuFe 2 As 2 43,44,[72][73][74] . This is further supported from density functional calculations on the superconducting CeO 0.5 F 0.5 BiS 2 , which suggest that the rare-earth band is isolated away from the Fermi Surface 75 .…”

Superconductivity and ferromagnetism in EuFe2(As1−xPx)2

“…Our recent magnetic Compton scattering experiment for EuFe 2 (As 0.73 P 0.27 ) 2 also confirms this scenario. [36] suggested that SC only coexists with Eu-AFM. However, their following work reconciled the discrepancy in terms of the canting of Eu 2+ spins.…”

Magnetic structure of theEu2+moments in superconductingEuFe2(As1−xNandi1, Jin2, Xiao3 et al. 2014Phys. Rev. B407320View full textAdd to dashboardCite

“…However, the exact nature of the Eu 2+ magnetic order within the superconducting dome remained controversial [22]. Most surprising is the coexistence of ferromagnetism and superconductivity as recently proposed by many groups for the P-doped EuFe 2 As 2 samples [22][23][24][25][26]. In particular, Zapf et al [22,26] concluded based on macroscopic measurements that the Eu 2+ moments in EuFe 2 (As 1−x P x ) 2 order in a canted A-type antiferromagnetic structure with the spin component along the c direction being ferromagnetically aligned.…”