Browsing by Author "Bauer, ED"

Now showing 1 - 3 of 3
  • No Thumbnail Available
    Item
    First-order phase transition in a new CaCu5-related antimonide, CePt5Sb
    (American Chemical Society, 2011-09-13) Salamakha, L; Bauer, ED; Michor, H; Hilscher, G; Muller, H; Svagera, R; Sologub, O; Rogl, P; Hester, JR; Roisnel, T; Giester, G; Mudryi, S
    A new CaCu(5) related antimonide, CePt(5)Sb, has been identified. This ternary compound undergoes a structural phase transition at about 80 K according to room- and low-temperature X-ray and neutron diffraction, and measurements of electrical resistivity, specific heat and magnetism. The room temperature phase forms a new rhombohedral structure, space group R (3) over bar, a = 0.53535(2) nm, c = 3.10814(12) nm and consists of alternating blocks of CaCu(5)- and MnCu(2)Al-type fragments that extend along the c-axis. The low-temperature phase is monoclinic, space group Cm, a = 0.91821(5) nm, b = 0.53696(1) nm, c = 1.08064(6) nm, beta = 107.40(1)degrees. The unit cells of both structures (orthohexagonal and monoclinic) are geometrically related via the transformation matrix a' = -b', b' = -a, c'=1/3b - 1/3c. Bulk properties elucidate the phase transition being of first-order and evidence Kondo interactions at low temperatures. © 2011, American Chemical Society
  • No Thumbnail Available
    Item
    Kondo behavior, ferromagnetic correlations, and crystal fields in the heavy-fermion compounds Ce3X (X = In, Sn).
    (American Physical Society, 2010-06-25) Wang, CH; Lawrence, JM; Christianson, AD; Goremychkin, EA; Fanelli, VR; Gofryk, K; Bauer, ED; Ronning, F; Thompson, JD; de Souza, NR; Kolesnikov, AI; Littrell, KC
    We report measurements of inelastic neutron scattering, magnetic susceptibility, magnetization, and the magnetic field dependence of the specific heat for the heavy Fermion compounds Ce3In and Ce3Sn. The neutron scattering results show that the excited crystal field levels have energies E1=13.2 meV, E2=44.8 meV for Ce3In and E1=18.5 meV, E2=36.1 meV for Ce3Sn. The Kondo temperature deduced from the quasielastic linewidth is 17 K for Ce3In and 40 K for Ce3Sn. The low-temperature behavior of the specific heat, magnetization, and susceptibility cannot be well described by J=1/2 Kondo physics alone, but require calculations that include contributions from the Kondo effect, broadened crystal fields, and ferromagnetic correlations, all of which are known to be important in these compounds. We find that in Ce3In the ferromagnetic fluctuation makes a 10%–15% contribution to the ground state doublet entropy and magnetization. The large specific heat coefficient γ in this heavy fermion system thus arises more from the ferromagnetic correlations than from the Kondo behavior. © 2010, American Physical Society
  • Thumbnail Image
    Item
    Topological barrier for skyrmion lattice formation in MnSi
    (Australian Institute of Nuclear Science and Engineering (AINSE), 2020-11-11) Leishman, A; Menezes, RM; Longbons, G; Bauer, ED; Janoschek, M; Honecker, D; Debeer-Schmitt, L; White, JS; Sokolova, AV; Milosevic, MV; Eskildsen, MR
    We report the observation of a topological skyrmion energy barrier through a hysteresis of the skyrmion lattice in the prototypical helimagnet MnSi. Measurements of the energy barrier were made using smallangle neutron scattering and a bespoke DC field coil to allow for high-precision hysteresis loops. Data has been analyzed using an adapted Preisach model to quantify the energy barrier for skyrmion formation and the magnetic behavior of the sample as a whole. This analysis was then compared with minimum-energy path analysis based on atomistic spin simulations to verify the topological nature of the barrier. This reveals that the skyrmion lattice in MnSi forms with an activation barrier of several eV and in domains that are several hundred skyrmions in size.