ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Previous empirical or semiempirical potentials for use in atomic computer simulation in iron and its alloys1,2 have not explicitly taken account of the magnetism per se, but because the magnetic effects have contributed to the mechanical and thermal properties used in choosing the parameters of the potential, it would not be accurate to say that these potentials ignore the magnetic effects completely. However, for cases where the magnetic properties significantly change about defects in crystal, these potentials may be inadequate to simulate their structures or energies. We try to remedy this situation by a modification of the embedded-atom method (EAM) for obtaining interatomic potentials, in which the EAM potential for nonmagnetic iron is first obtained, and then extra terms in the potential are introduced to match the magnetic interactions. These interactions may be obtained by comparison of the properties of both nonmagnetic and magnetic iron as obtained, say, by doing both a non-spin-polarized and a spin-polarized computation for bcc iron. We have actually used the Stoner method in conjunction with a linear muffin-tin orbitals computation of nonmagnetic iron3 to calculate the magnetic contribution to energy, since the Stoner parameter is adjusted to fit experimental data and, therefore, the method is perhaps more suitable for determining an empirical potential than are the currently available a priori theoretical methods. We then use the experimental values of the cohesive energy and elastic constants, but with the magnetic contributions subtracted out, to fit the nonmagnetic iron EAM potential. Additional terms in the potential are then added to reproduce the magnetic effects.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.344879
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