The first-principles study of thermodynamical properties of random magnetic overlayers on fcc-Cu(001) substrate
arXiv:1212.4057 · doi:10.1103/PhysRevB.87.075452
Abstract
We present the theoretical study of thermodynamical properties of fcc-Cu(001) substrate covered by iron-cobalt monolayer as well as by incomplete iron layer. The effective two-dimensional Heisenberg Hamiltonian is constructed from first principles and properties of exchange interactions are investigated. The Curie temperatures are estimated using the Monte-Carlo (MC) simulations and compared with a simplified approach using the random-phase approximation (RPA) in connection with the virtual-crystal approach (VCA) to treat randomness in exchange integrals. Calculations indicate a weak maximum of the Curie temperature as a function of composition of the iron-cobalt overlayer. While a good quantitative agreement between RPA-VCA and MC was found for iron-cobalt monolayer, the RPA-VCA approach fails quantitatively for low coverage due to the magnetic percolation effect. We also present the study of the effect of alloy disorder on the shape of magnon spectra of random overlayers.
9 pages, 7 figures, submitted to Phys. Rev. B
References in corpus (9)
- A method for atomistic spin dynamics simulations: implementation and examples
- First-principles prediction of high Curie temperature for ferromagnetic bcc-Co and bcc-FeCo alloys and its relevance to tunneling magnetoresistance
- Stable and fast semi-implicit integration of the stochastic Landau-Lifshitz equation
- Square lattice site percolation at increasing ranges of neighbor interactions
- Spin waves in paramagnetic BCC iron: spin dynamics simulations
- Two-dimensional anisotropic Heisenberg antiferromagnet in a field
- Substrate-induced antiferromagnetism of an Fe monolayer on the Ir(001) surface
- Phase transition in ultrathin magnetic films with long-range interactions: Monte Carlo simulation of the anisotropic Heisenberg model
- Dynamical properties of a three-dimensional diluted Heisenberg model