Thermodynamics of L1{sub 0} ordering in FePt nanoparticles studied by Monte Carlo simulations based on an analytic bond-order potential

Journal Article · Mon Oct 15 00:00:00 EDT 2007 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PHYSREVB.76.155412· OSTI ID:21052728

Mueller, Michael; Erhart, Paul; Albe, Karsten ^[1]

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1. Institut fuer Materialwissenschaft, Technische Universitaet Darmstadt, D-64287 Darmstadt (Germany)

The size dependence of the order-disorder transition in FePt nanoparticles with an L1{sub 0} structure is investigated by means of Monte Carlo simulations based on an analytic bond-order potential for FePt. A cross parametrization for the Fe-Pt interaction is proposed, which complements existing potentials for the constituents Fe and Pt. This FePt potential properly describes structural properties of ordered and disordered phases, surface energies, and the L1{sub 0} to A1 transition temperature in bulk FePt. The potential is applied for examining the ordering behavior in small particles. The observed lowering of the order-disorder transition temperature with decreasing particle size confirms previous lattice-based Monte Carlo simulations [M. Mueller and K. Albe, Phys. Rev. B 72, 094203 (2005)]. Although a distinctly higher amount of surface induced disorder is found in comparison to previous studies based on lattice-type Hamiltonians, the presence of lattice strain caused by the tetragonal distortion of the L1{sub 0} structure does not have a significant influence on the depression of the ordering temperature with decreasing particle size.

• OSTI ID: 21052728
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Vol. 76, Issue 15; Other Information: DOI: 10.1103/PhysRevB.76.155412; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
36 MATERIALS SCIENCE
COMPARATIVE EVALUATIONS
COMPUTERIZED SIMULATION
HAMILTONIANS
IRON ALLOYS
MONTE CARLO METHOD
NANOSTRUCTURES
ORDER-DISORDER TRANSFORMATIONS
PARTICLE SIZE
PARTICLES
PLATINUM ALLOYS
POTENTIALS
SURFACE ENERGY
SURFACES
THERMODYNAMICS
TRANSITION TEMPERATURE