Pui-Wai Ma S. L. Dudarev C. H. Woo
We develop an atomistic spin-lattice-dynamics model for simulating energy relaxation in magnetic materials. The model explicitly solves equations of motion for the atoms and spins, and includes interaction with electron excitations. We apply the model to simulate the dynamics of propagation of a compressive elastic wave in iron. We find that coupli…
PublishedPui-Wai Ma W. C. Liu C. H. Woo S. L. Dudarev
We perform large-scale molecular dynamics simulations to study the magnetic properties of amorphous iron under pressure. Simulations, exceeding by at least two orders of magnitude those accessible to density functional calculations, use the recently developed magnetic interatomic potential for iron. The distributions of the size of atomic magnetic …
PublishedM. Yu. Lavrentiev R. Soulairol Chu-Chun Fu D. Nguyen-Manh S. L. Dudarev
Noncollinear configurations of local magnetic moments at Fe/Cr interfaces in Fe-Cr alloys are explored using a combination of density functional theory (DFT) and magnetic cluster expansion (MCE) simulations. We show that magnetic frustration at Fe/Cr interfaces can be partially resolved through the formation of noncollinear magnetic structures, whi…
PublishedP. M. Derlet M. R. Gilbert S. L. Dudarev
Nanoscale prismatic loops are modeled via a partial stochastic differential equation that describes an overdamped continuum elastic string, with a view to describing both the internal and collective dynamics of the loop as a function of temperature. Within the framework of the Langevin equation, expressions are derived that relate the empirical par…
PublishedM. Muzyk D. Nguyen-Manh K. J. Kurzydlowski N. L. Baluc S. L. Dudarev
The structure and phase stability of binary tungsten-vanadium and tungsten-tantalum alloys are investigated over a broad range of alloy compositions using ab initio and cluster expansion methods. The alloys are characterized by the negative enthalpy of mixing across the entire composition range. Complex intermetallic compounds are predicted by ab i…
PublishedPui-Wai Ma S.L. Dudarev
Microscopic stochastic Langevin-type spin dynamics equations provide a convenient and tractable model describing the relaxation of spin and spin-lattice ensembles.We develop a robust and numerically stable algorithm for integrating the Langevin spin dynamics equations, and explore, both numerically and analytically, a range of applications of the m…
PublishedM.Yu. Lavrentiev S.L. Dudarev D. Nguyen-Manh
Magnetic Cluster Expansion model is developed for bcc Fe-Cr alloys, and applied to the investigation of magnetic properties of these alloys for a broad interval of concentrations ranging from pure Fe to pure Cr, and for a broad interval of temperatures extending well over 1000 K. Finite-temperature configurations simulated using the Magnetic Cluste…
PublishedM.R. Gilbert S.L. Dudarev S. Zheng L.W. Packer J.-Ch. Sublet
In a fusion reactor, materials will be subjected to significant fluxes of high-energy neutrons. As well as causing radiation damage, the neutrons also initiate nuclear reactions leading to changes in the chemical composition of materials (transmutation). Many of these reactions produce gases, particularly helium, which cause additional swelling and…
PublishedS. L. Dudarev M. R. Gilbert K. Arakawa H. Mori Z. Yao M.L. Jenkins P.M. Derlet
In situ real-time electron microscope observations of metals irradiated with ultrahigh-energy electrons or energetic ions show that the dynamics of microstructural evolution in these materials is strongly influenced by long-range elastic interactions between mobile nanoscale radiation defects. Treating long-range interactions is also necessary for …
Published