Spin reorientation of the Fe moments in Eu0.5Ca0.5Fe2As2: Evidence for strong interplay of Eu and Fe magnetism

Article

关键词: MAGNON GAP;    IRON;    SUPERCONDUCTIVITY;    ANTIFERROMAGNET;    SCATTERING;    PNICTIDES;   

DOI  :  10.1103/PhysRevB.99.140402

来源: SCIE

【 摘 要 】

Using complementary polarized and unpolarized single-crystal neutron diffraction, we have investigated the temperature-dependent magnetic structures of Eu0.5Ca0.5Fe2As2. Upon 50% dilution of the Eu sites with isovalent Ca2+, the Eu sublattice is found to be still long-range ordered below T-Eu = 10 K, in the A-type antiferromagnetic (AFM) structure. The moment size of Eu2+ spins is estimated to be as large as 6.74(4)mu(B) at 2.5 K. The Fe sublattice undergoes a spin-density-wave transition at T-SDW = 192(2) K and displays an in-plane AFM structure above T-Eu. However, at 2.5 K, the Fe2+ moments are found to be ordered in a canted AFM structure with a canting angle of 14(4)degrees out of the ab plane. The spin reorientation of Fe below the AFM ordering temperature of Eu provides direct evidence of a strong interplay between the two magnetic sublattices in Eu0.5Ca0.5Fe2As2.

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