Anisotropic superconductivity in Eu(Fe0.75Ru0.25)2As2 ferromagnetic superconductor
Department of Physics, Zhejiang University - Hangzhou 310027, China
2 State Key Lab of Silicon Materials, Zhejiang University - Hangzhou 310027, China
3 Racah Institute of Physics, The Hebrew University - Jerusalem 91904, Israel
Accepted: 8 August 2011
We report an unprecedented anisotropic superconductivity in Eu(Fe0.75Ru0.25)2As2 single crystals. The in-plane resistivity (ρab) and vertical magnetization (Mc) show a superconducting transition at TSC=23 K with zero resistance and magnetic shielding, respectively. In comparison, the out-of-plane resistivity (ρc) does not go to zero, neither does the horizontal magnetization (Mab) show the shielding against external fields. Magnetization and Mössbauer data indicate that the Eu2+ spins order ferromagnetically below 19.5 K with the moments tilted 20° from the c-axis. Our result suggests spontaneous-vortex phase and/or Fulde-Ferrell-Larkin-Ovchinnikov state in the ferromagnetic superconductor.
PACS: 74.70.Xa – Pnictides and chalcogenides / 74.25.F- – Transport properties / 74.25.Ha – Magnetic properties including vortex structures and related phenomena
© EPLA, 2011