Browsing by Author "Diallo, SO"
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- ItemAnisotropic three-dimensional magnetism in CaFe2As2(American Physical Society, 2008-11-28) McQueeney, RJ; Diallo, SO; Antropov, VP; Samolyuk, GD; Broholm, C; Ni, N; Nandi, S; Yethiraj, M; Zarestky, JL; Pulikkotil, JJ; Kreyssig, A; Lumsden, MD; Harmon, BN; Canfield, PC; Goldman, AIInelastic neutron scattering measurements of the magnetic excitations in CaFe2As2 indicate that the spin wave velocity in the Fe layers is exceptionally large and similar in magnitude to the cuprates. However, the spin wave velocity perpendicular to the layers is at least half as large that in the layer, so that the magnetism is more appropriately categorized as anisotropic three-dimensional, in contrast to the two-dimensional cuprates. Exchange constants derived from band structure calculations predict spin wave velocities that are consistent with the experimental data. © 2008, American Physical Society
- ItemLow energy spin dynamics in the spin ice Ho2Sn2O7(Intitite of Physics Publishing Ltd, 2012-02-22) Ehlers, G; Huq, A; Diallo, SO; Adriano, C; Rule, KC; Cornelius, AL; Fouquet, P; Pagliuso, PG; Gardner, JSThe magnetic properties of Ho 2 Sn 2 O 7 have been investigated and compared to other spin ice compounds. Although the lattice has expanded by 3% relative to the better studied Ho 2 Ti 2 O 7 spin ice, no significant changes were observed in the high temperature properties, T greater than or similar to 20 K. As the temperature is lowered and correlations develop, Ho 2 Sn 2 O 7 enters its quantum phase at a slightly higher temperature than Ho 2 Ti 2 O 7 and is more antiferromagnetic in character. Below 80 K a weak inelastic mode associated with the holmium nuclear spin system has been measured. The hyperfine field at the holmium nucleus was found to be ≈700 T. (c) 2012 IOP Publishing LTD