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Friday, May 03

Effect of Spin-Lattice Coupling on Magnetic Phase Transition of BCC Iron

Junqi Yin, Ph.D., Oak Ridge National Laboratory, Oak Ridge
National Institute for Computational Sciences Seminar
1:00 PM — 2:00 PM, Joint Institute for Computational Sciences (JICS), Building 5100, Room 128, Lecture Hall
Contact: Lonnie Crosby (lcrosby1@utk.edu), 865.241.3404

Abstract

For empirical iron potentials, the magnetic contribution is usually implicitly considered, and the spin-lattice coupling is simply neglected. From first principle calculations, we proposed a Heisenberg-type of exchange for bcc iron that couples the spin and lattice degrees of freedom. The parameterization is based on quantities already employed in embedded-atom potentials. Therefore, the model is a natural augmentation of the existing iron potentials, and is applicable to molecular dynamics simulations. Our model built on Dudarev potential can reproduce iron's specific heat from the Curie temperature down to about 400K, and the estimate of the spin-lattice contribution indicates that it is significant near the transition.