Ferromagnetic Excitations in La$_{0.82}$Sr$_{0.18}$CoO$_{3}$ Observed Using Neutron Inelastic Scattering

R. A. Ewings; P. G. Freeman; M. Enderle; J. Kulda; D. Prabhakaran; A. T. Boothroyd

doi:10.1103/physrevb.82.144401

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arXiv · 1007.1919

Ferromagnetic Excitations in La$_{0.82}$Sr$_{0.18}$CoO$_{3}$ Observed Using Neutron Inelastic Scattering

R. A. Ewings·P. G. Freeman·M. Enderle·J. Kulda·D. Prabhakaran·A. T. Boothroyd

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Abstract

Polarized neutron inelastic scattering has been used to measure spin excitations in ferromagnetic La$_{0.82}$Sr$_{0.18}$CoO$_{3}$. The magnon spectrum of these spin excitations is well defined at low energies but becomes heavily damped at higher energies, and can be modeled using a quadratic dispersion. We determined a spin wave stiffness constant of $D=94\pm 3$\,meV\,Å$^{2}$. Assuming a nearest-neighbor Heisenberg model we find reasonable agreement between the exchange determined from D and the bulk Curie temperature. Several possible mechanisms to account for the observed spin-wave damping are discussed.

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R. A. Ewings, P. G. Freeman, M. Enderle, J. Kulda, D. Prabhakaran, A. T. Boothroyd. 2010-07-12. Ferromagnetic Excitations in La$_{0.82}$Sr$_{0.18}$CoO$_{3}$ Observed Using Neutron Inelastic Scattering. https://doi.org/10.1103/physrevb.82.144401

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