Browsing by Author "Broholm, C"

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    Anisotropic 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, AI
    Inelastic 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
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    Magnetic field splitting of the spin resonance in CeCoIn5
    (American Physical Society, 2012-10-17) Stock, C; Broholm, C; Zhao, Y; Demmel, F; Kang, HJ; Rule, KC; Petrovic, C
    Neutron scattering in strong magnetic fields is used to show the spin resonance in superconducting CeCoIn(5) (T(c) = 2.3 K) is a doublet. The underdamped resonance ((h) over bar Gamma = 0.069 +/- 0.019 meV) Zeeman splits into two modes at E(+/-) = (h) over bar Omega(0) +/- mu(B mu 0)H with alpha = 0.96 +/- 0: 05. A linear extrapolation of the lower peak reaches zero energy at 11.2 +/- 0.5 T, near the critical field for the incommensurate "Q phase." Kenzelmann et al. [Science 321, 1652 (2008)] This, taken with the integrated weight and polarization of the low-energy mode (E(-)), indicates that the Q phase can be interpreted as a Bose condensate of spin excitons. © 2012, American Physical Society.