title: Effect of uniaxial strain on the structural and magnetic phase transitions in BaFe2As2.
abstract: We report neutron scattering experiments probing the influence of uniaxial strain on both the magnetic and structural order parameters in the parent iron pnictide compound, BaFe2As2. Our data show that modest strain fields along the in-plane orthorhombic b axis can affect significant changes in phase behavior simultaneous to the removal of structural twinning effects. As a result, we demonstrate in BaFe2As2 samples detwinned via uniaxial strain that the in-plane C4 symmetry is broken by both the structural lattice distortion and long-range spin ordering at temperatures far above the nominal (strain-free) phase transition temperatures. Surprising changes in the magnetic order parameter of this system under relatively small strain fields also suggest the inherent presence of magnetic domains fluctuating above the strain-free ordering temperature in this material.
authors.affiliation: Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467, USA.
authors.forename: Chetan
authors.initials: C
authors.lastname: Dhital
authors.forename: Z
authors.initials: Z
authors.lastname: Yamani
authors.forename: Wei
authors.initials: W
authors.lastname: Tian
authors.forename: J
authors.initials: J
authors.lastname: Zeretsky
authors.forename: A S
authors.initials: AS
authors.lastname: Sefat
authors.forename: Ziqiang
authors.initials: Z
authors.lastname: Wang
authors.forename: R J
authors.initials: RJ
authors.lastname: Birgeneau
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Wilson