paper

Strong coupling between magnetic and structural order parameters in SrFe2As2

arXiv:0807.0632 · doi:10.1103/PhysRevB.78.180504

Abstract

X-ray and Neutron diffraction as well as muon spin relaxation and MÃ¶ssbauer experiments performed on SrFe $_{2}$ As $_{2}$ polycrystalls confirm a sharp first order transition at $T_{0} = 205$ ,K corresponding to an orthorhombic phase distortion and to a columnar antiferromagnetic Fe ordering with a propagation vector (1,0,1), and a larger distortion and larger size of the ordered moment than reported for BaFe $_{2}$ As $_{2}$ . The structural and the magnetic order parameters present an remarkable similarity in their temperature dependence from $T_{0}$ down to low temperatures, showing that both phenomena are intimately connected. Accordingly, the size of the ordered Fe moments scale with the lattice distortion when going from SrFe $_{2}$ As $_{2}$ to BaFe $_{2}$ As $_{2}$ . Full-potential band structure calculations confirm that the columnar magnetic order and the orthorhombic lattice distortion are intrinsically tied to each other.

10 pages, 4 figures