Atomic Ordering in Nano-layered FePt: Multiscale Monte Carlo Simulation

AbstractCombined nano- and mesoscale simulation of chemical ordering kinetics in nano-layered L10 AB binary system was performed. In the nano- (atomistic) scale Monte Carlo (MC) technique with vacancy mechanism of atomic migration was implemented with diverse system models. The mesoscale microstructure evolution was, in turn, modeled by means of MC procedure simulating antiphase boundary (APB) motion as controlled by APB energies evaluated within the nano-scale simulations. The study addressed FePt thin layers considered as a material for ultra-high density magnetic storage media and revealed metastability of the L10 c-variant superstructure with monoatomic planes parallel to the (001) free surface and off-plane easy magnetization. The layers, initially perfectly ordered in the L10 c-variant, showed homogenous disordering running in parallel with a spontaneous re-orientation of the monoatomic planes into a mosaic-microstructure composed of L10 a- and b-variant domains with (100)- and (010)-type monoatomic planes, respectively. The domains nucleated heterogeneously on the Fe free surface of the layer, grew discontinuously inwards its volume and finally relaxed generating an equilibrium microstructure of the system. Two �atomistic-scale� processes: (i) homogenous disordering and (ii) nucleation of the L10 a- and b-variant domains showed characteristic time scales. The same was observed for the meso-scale processes: (i) heterogeneous L10 variant domain growth and (ii) domain microstructure relaxation. The above phenomena modelled within the present study by means of multiscale MC simulations have recently been observed experimentally in epitaxially deposited thin films of FePt.

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Atomic-Migration-Controlled Processes in Intermetallics

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.277.113 ◽

2008 ◽

Vol 277 ◽

pp. 113-118 ◽

Cited By ~ 3

Author(s):

Rafal Abdank-Kozubski ◽

Andrzej Biborski ◽

Mirosław Kozłowski ◽

Christine Goyhenex ◽

Veronique Pierron-Bohnes ◽

...

Keyword(s):

Vacancy Concentration ◽

Mean Field ◽

Pair Interaction ◽

Antisite Defect ◽

Thin Layers ◽

Magnetic Storage ◽

Easy Magnetization ◽

Chemical Ordering ◽

Ordering Kinetics ◽

Thermal Vacancy

Chemical ordering kinetics in L10- and B2-ordered AB binary intermetallics was simulated by means of Monte Carlo (MC) technique implemented with vacancy mechanism of atomic migration. While vacancy concentration is usually much lower than the antisite defect concentration in L10-ordered systems, triple defects are generated in particular B2–ordered systems. The latter definitely affects the chemical ordering process and requires that full thermal vacancy thermodynamics is involved in B2-ordering simulations. The study on L10-ordered binaries was dedicated to FePt thin layers considered as a material for ultra-high-density magnetic storage media. Metastability of the L10 c-variant with monoatomic planes parallel to the layer surface and off-plane easy magnetization was revealed. Thermal vacancy formation in B2-ordered binaries was modelled by implementing a mean-field Hamiltonian with a specific formalism of phase equilibria in a latticegas composed of atoms and vacancies. It was demonstrated that for particular pair-interaction energetics, equilibrium concentrations of vacancies and antisites result mutually proportional in well-defined temperature ranges. The MC simulations of B2-ordering kinetics involved the modelled equilibrium vacancy concentration and reproduced the experimentally observed low rate of the process.

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Effect of Fe Addition on Ordering Kinetics in Ni3Al1-xFex System. Monte Carlo Simulation

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.263.93 ◽

2007 ◽

Vol 263 ◽

pp. 93-98 ◽

Cited By ~ 1

Author(s):

E. Partyka ◽

Rafal Abdank-Kozubski

Keyword(s):

Monte Carlo Simulation ◽

Monte Carlo ◽

Model System ◽

Chemical Ordering ◽

Ordering Kinetics ◽

Ternary Element ◽

Antisite Defects ◽

Kinetics Of ◽

Fe Addition

The influence of Fe admixture on ordering kinetics in Ni3Al1-xFex was studied by running Monte Carlo simulations in a model system A3B1-xCx showing similarly to Ni3Al1-xFex destabilization of the ordered phase when admixing a ternary element C. Detailed analysis of atomic jump statistics revealed a dominance of the C-atom jumps in the creation/elimination of antisite defects as well as in the migration of antisites within majority sublattice. The results elucidate the role of Fe alloying in the kinetics of chemical ordering in Ni3Al.

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Structural Properties of Fe/Cu Magnetic Multilayers: A Monte Carlo Approach

SPIN ◽

10.1142/s2010324718500121 ◽

2018 ◽

Vol 08 (03) ◽

pp. 1850012

Author(s):

Jules Berlin Nde Kengne ◽

Bernard Fongang ◽

Serge Zekeng

Keyword(s):

Monte Carlo ◽

Structural Properties ◽

Magnetic Multilayers ◽

The Body ◽

Magnetic Storage ◽

Face Centered Cubic ◽

Magnetic Layers ◽

Face Centered ◽

Magnetic Storage Media ◽

The Impact

Using atomistic Monte Carlo simulations, we investigated the impact of the interface on the structural properties of iron and copper (Fe/Cu) magnetic multilayers grown by Voronoi diagram. Interest in magnetic multilayers has recently emerged as they are shown to be promising candidates for magnetic storage media, magneto-resistive sensors and personalized medical treatment. As these artificial materials show large differences in properties compared to conventional ones, many experimental and theoretical works have been dedicated on shedding light on these differences and tremendous results have emerged. However, little is known about the influence of the interfaces on magnetic layers. Using numerical approaches, we show that the structure of each layer depends on its thickness and the interface morphology. The Fe and Cu layers can adopt either the body-centered-cubic (bcc) or face-centered-cubic (fcc) structure, while the interface can assume amorphous, bcc, fcc, or a mixture of bcc and fcc structures depending on the layer thicknesses. These results are in good agreement with the experiments. They could be helpful in understanding effects such as giant magneto-resistance from the structural perspective.

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ORDERING KINETICS BY VACANCIES

International Journal of Modern Physics C ◽

10.1142/s0129183193000604 ◽

1993 ◽

Vol 04 (03) ◽

pp. 701-720 ◽

Cited By ~ 13

Author(s):

EDUARD VIVES ◽

ANTONI PLANES

Keyword(s):

Phase Transition ◽

Monte Carlo Simulation ◽

Monte Carlo ◽

State Of The Art ◽

Growth Dynamics ◽

Domain Growth ◽

Disorder Phase Transition ◽

Ordering Kinetics ◽

Simulation Results ◽

Domain Growth Dynamics

Domain growth dynamics in binary alloys undergoing an order-disorder phase transition is revised. After a summary of the state-of-the-art of the problem, we focus on the Monte Carlo simulation results. The usual atom-exchange dynamics is compared with a more realistic vacancy driven dynamics. Results suggest that the expected Allen-Cahn growth law might be modified by this more realistic dynamics.

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New advances on Au–magnetic organic hybrid core–shells in MRI, CT imaging, and drug delivery

RSC Advances ◽

10.1039/d1ra00415h ◽

2021 ◽

Vol 11 (12) ◽

pp. 6517-6525

Author(s):

Fatemeh Mohajer ◽

Ghodsi Mohammadi Ziarani ◽

Alireza Badiei

Keyword(s):

Magnetic Resonance Imaging ◽

Drug Delivery ◽

Magnetic Nanoparticles ◽

Targeted Drug Delivery ◽

Magnetic Storage ◽

Resonance Imaging ◽

Organic Hybrid ◽

Storage Media ◽

Targeted Drug ◽

Magnetic Storage Media

Magnetic nanoparticles have been studied for scientific and technological applications such as magnetic storage media, contrast agents for magnetic resonance imaging, biolabelling, separation of biomolecules, and magnetic-targeted drug delivery.

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Monte Carlo simulations of the free surface of polymer melts

Chemical Engineering Science ◽

10.1016/0009-2509(94)e0108-3 ◽

1994 ◽

Vol 49 (17) ◽

pp. 2899-2906 ◽

Cited By ~ 14

Author(s):

Sanat K. Kumar ◽

Thomas P. Russell ◽

Arvind Hariharan

Keyword(s):

Monte Carlo ◽

Free Surface ◽

Monte Carlo Simulations ◽

Polymer Melts

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Simulation of Thermal Cooling Curves in the Process to Ordering Alloys by the Monte Carlo Method

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.410.227 ◽

2021 ◽

Vol 410 ◽

pp. 227-234

Author(s):

Albert R. Khalikov ◽

Sergey V. Dmitriev

Keyword(s):

Monte Carlo ◽

Monte Carlo Method ◽

Stoichiometric Composition ◽

Square Lattice ◽

Cooling Curves ◽

Ordering Kinetics ◽

The Monte Carlo Method ◽

Proposed Model ◽

Coordination Spheres ◽

Thermal Cooling

An algorithm is proposed for constructing curves of thermal cooling and ordering kinetics with a monotonic decrease in temperature for alloys to stoichiometric composition. Modeling is carried out by the Monte Carlo method in the model of a rigid crystal lattice and pair interatomic interactions. The application of the algorithm is illustrated by the example to a square lattice, taking into account interatomic interactions in the first two coordination spheres for alloys with the composition AB, A3B, and A3B5. The proposed model makes it possible to calculate individual sections of the phase diagrams to the state for binary alloys.

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Monte Carlo simulations of long-range order kinetics in B2 phases

Journal of Materials Research ◽

10.1557/jmr.1995.0591 ◽

1995 ◽

Vol 10 (3) ◽

pp. 591-595 ◽

Cited By ~ 18

Author(s):

K. Yaldram ◽

V. Pierron-Bohnes ◽

M.C. Cadeville ◽

M.A. Khan

Keyword(s):

Monte Carlo ◽

Monte Carlo Simulations ◽

Nearest Neighbor ◽

Vacancy Concentration ◽

Relaxation Times ◽

Nearest Neighbors ◽

Migration Energy ◽

Ordering Kinetics ◽

Migration Barriers ◽

Temperature Dependences

The thermodynamic parameters that drive the atomic migration in B2 alloys are studied using Monte-Carlo simulations. The model is based on a vacancy jump mechanism between nearest neighbor sites, with a constant vacancy concentration. The ordering energy is described through an Ising Hamiltonian with interaction potentials between first and second nearest neighbors. Different migration barriers are introduced fur A and B atoms. The results of the simulations compare very well with those of experiments. The ordering kinetics are well described by exponential-like behaviors with two relaxation times whose temperature dependences are Arrhenius laws yielding effective migration energies. The ordering energy contributes significantly to the total migration energy.

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