Browsing by Author "Constable, E"

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Complementary terahertz absorption and inelastic neutron study of the dynamic anisotropy contribution to zone-center spin waves in a canted antiferromagnet NdFeO3
    (APS Physics, 2014-08-19) Constable, E; Cortie, DL; Horvat, J; Lewis, RA; Cheng, Z; Deng, G; Cao, S; Yuan, S; Ma, G
    We employ a combination of pulsed- and continuous-wave polarized terahertz spectroscopy techniques to probe temperature-dependent spin waves in the antiferromagnet NdFeO3. Our optical data span 1.6–467 K and reveal a conspicuous spin reorientation between 110 and 170 K, during which the lower-energy mode softens completely. Complementary inelastic neutron scattering reveals that the frequencies of the optically excited spin waves are consistent with a temperature-variable spin gap in the low-energy spin-wave dispersion of NdFeO3. The result links the temperature dependence of the spin waves to a dynamic in-plane anisotropy. The magnetic anisotropy is calculated based on the results of the optical measurements. The change observed in the anisotropy energy along the a and c crystal axes suggests that the spin reorientation evident in NdFeO3 is driven by temperature-dependent in-plane anisotropy.© 2014, American Physical Society.
  • No Thumbnail Available
    Item
    High temperature anisotropy of NdFeO3 determined using time-domain THz spectroscopy
    (Institute of Electrical and Electronics Engineers (IEEE), 2013-09) Constable, E; Horvat, J; Cortie, DL; Cheng, Z; Yuan, S; Cao, SX; Lewis, RA
    The temperature dependent anisotropic fields along two principal crystallographic axes (Ax and Az) is calculated for the canted antiferromagnet neodymium iron oxide in the temperature range 300 - 470 K. The calculation is performed using the experimentally determined temperature dispersion of two orthogonal antiferromagnetic magnons, obtained via time-domain terahertz spectroscopy. The experiment demonstrates the potential use of THz spectroscopy for characterising magnetic materials and offers a complementary technique to traditional neutron and magnetic methods. © 2013 IEEE.