Combined molecular dynamics-spin dynamics simulations of bcc iron

Conference · Fri Aug 01 00:00:00 EDT 2014

DOI:https://doi.org/10.1088/1742-6596/487/1/012007· OSTI ID:1124508

Perera, Meewanage Dilina ^[1]; Yin, Junqi  ^[1]; Landau, David P. ^[2]; Nicholson, Don M. ^[1]; Stocks, George  ^[1]; Eisenbach, Markus  ^[1]; Brown, Greg ^[1]

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1. ORNL
2. University of Georgia, Athens

Using a classical model that treats translational and spin degrees of freedom on an equal footing, we study phonon-magnon interactions in BCC iron with combined molecular and spin dynamics methods. The atomic interactions are modeled via an empirical many-body potential while spin dependent interactions are established through a Hamiltonian of the Heisenberg form with a distance dependent magnetic exchange interaction obtained from first principles electronic structure calculations. The temporal evolution of translational and spin degrees of freedom was determined by numerically solving the coupled equations of motion, using an algorithm based on the second order Suzuki-Trotter decomposition of the exponential operators. By calculating Fourier transforms of space- and time-displaced correlation functions, we demonstrate that the the presence of lattice vibrations leads to noticeable softening and damping of spin wave modes. As a result of the interplay between lattice and spin subsystems, we also observe additional longitudinal spin wave excitations, with frequencies which coincide with that of the longitudinal lattice vibrations.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1124508
• Resource Relation: Journal Volume: 487; Conference: 7th Brazilian Meeting on Simulational Physics - Joao Pessoa, , Brazil - 8/5/2013 12:00:00 AM-8/10/2013 12:00:00 AM
• Country of Publication: United States
• Language: English