mu SR and neutron diffraction investigations on the reentrant ferromagnetic superconductor Eu(Fe0.86Ir0.14)(2)As-2

作者：Anand V K^*; Adroja D T; Bhattacharyya A; Paramanik U B; Manuel P; Hillier A D; Khalyavin D; Hossain Z

来源：Physical Review B, 2015, 91(9): 094427.

DOI：10.1103/PhysRevB.91.094427

Results of muon spin relaxation (mu SR) and neutron powder diffraction measurements on a reentrant superconductor Eu(Fe0.86Ir0.14)(2)As-2 are presented. Eu(Fe0.86Ir0.14) As-2(2) exhibits superconductivity at T-con approximate to 22.5 K competing with long range ordered Eu+2 moments below approximate to 18 K. A reentrant behavior (manifested by nonzero resistivity in the temperature range 10-17.5 K) results from an exquisite competition between the superconductivity and magnetic order. The zero field mu SR data confirm the long range magnetic ordering below T-Eu = 18.7(2) K. The transition temperature is found to increase with increasing magnetic field in longitudinal field mu SR which along with the neutron diffraction results, suggests the transition to be ferromagnetic. The neutron diffraction data reveal a clear presence of magnetic Bragg peaks below T-Eu which could be indexed with propagation vector k = (0, 0, 0), confirming a long range magnetic ordering in agreement with mu SR data. Our analysis of the magnetic structure reveals an ordered magnetic moment of 6.29(5) mu(B) (at 1.8 K) on the Eu atoms and they form a ferromagnetic structure with moments aligned along the c axis. No change in the magnetic structure is observed in the reentrant or superconducting phases and the magnetic structure remains same for 1.8 K <= T <= T-Eu. No clear evidence of structural transition or Fe moment ordering was found.

• 出版日期2015-3-25