The effect of uniaxial tensile stress and the resultant strain on the structural/magnetic transition in the parent compound of the iron arsenide superconductor BaFe 2As 2 is characterized by temperature-dependent electrical resistivity, x-ray diffraction, and quantitative polarized light imaging. We show that strain induces a measurable uniaxial structural distortion above the first-order magnetic transition and significantly smears the structural transition. This response is different from that found in another parent compound, SrFe 2As 2, where the coupled structural and magnetic transitions are strongly first order. This difference in the structural responses explains the in-plane resistivity anisotropy above the transition in BaFe 2As 2. This conclusion is supported by the Ginzburg-Landau-type phenomenological model for the effect of the uniaxial strain on the resistivity anisotropy.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Apr 9 2012|