Spin dynamics across an inhomogeneous atomic boundary separating ultrathin Heisenberg ferromagnetic films

Belhadi, M.; Chadli, R.; Khater, A.; Ghantous, Michel Abou

doi:10.1051/epjap:2006124

Cited by 11 publications

(3 citation statements)

References 35 publications

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“…The understanding of coherent electronic transport in the mesoscopic regime has been 2 ISRN Condensed Matter Physics provided by the formalism of Landauer [21] and Büttiker [22] for electron transport in mesoscopic systems, who related the conductance of the system to its scattering matrix. Multiple scattering and quantum interference phenomena are not limited, however, to the electronic transport, but in a variety of problems they can become important for the coherent transport of other types of excitations such as phonons [23,24] and magnons [25,26] in low-dimensional systems.…”

Section: Introductionmentioning

confidence: 99%

Phonon Conductance of Potassium- and Sodium-Doped Transpolyacetylene Chain

Belhadi

Kheffache

2012

ISRN Condensed Matter Physics

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A theoretical approach for the study of phonon dynamics and scattering properties of doped transpolyacetylene chain is presented. The coherent reflection and transmission scattering cross-sections for phonons incident on the doped unit cell boundary are calculated in accordance with the Landauer-Buttiker electron scattering description, using the matching procedure with the nearest and next nearest neighbor elastic force constants. This is done for two different dopants, namely, the potassium and sodium atoms. Our numerical results yield an understanding of the transpolyacetylene chain dynamical properties and the effects on phonon conductance due to phonon incident on the doped unit cell boundary. The coherent reflection and transmission coefficients show characteristic spectral features, depending on the cutoff frequencies for the propagating phonons and on the nature of the dopants. They illustrate the occurrence of Fano resonances in the scattering spectra that result from the interactions of propagating elastic waves of the undoped transpolyacetylene chain with the localized modes due to the breakdown of the translation symmetry in the x direction.

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Section: Introductionmentioning

confidence: 99%

Phonon Conductance of Potassium- and Sodium-Doped Transpolyacetylene Chain

Belhadi

Kheffache

2012

ISRN Condensed Matter Physics

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“…10 This state of the art in nanomagnetism exists thanks to the technical advances towards preparing nanostructures, and to the important experimental information available by advanced characterization techniques. Because of the relevance of spin dynamics in nanoscale devices, the problem of travelling spin waves on nanostructures and of their transport, has received some attention in the past, 11 where imperfections can influence mode propagation through the medium, 12 providing a unique perspective on its microscopic behavior via several effects, such as localized states, wave reflection, and resonant scattering. The study of spin waves in low dimensional nanostructures has also proved useful for determining magnetic anisotropy effects.…”

Section: Introductionmentioning

confidence: 99%

“…They can become important for the coherent transport of other types of elementary excitations in low dimensional systems, as phonons and magnons. 11,12,18 At low temperatures, the devices are mesoscopic in the sense that their quantum states must be described by coherent wave functions extending over the entire system, and quantum-mechanical interference effects become (a) A schematic representation of a molecular junction connecting two semi-infinite ultrathin two-dimensional Heisenberg ferromagnetic films made up of three atomic layers each, with magnetic exchange interactions between nearest neighbors. For simplicity we take the same distance a between adjacent sites.…”

Section: Introductionmentioning

confidence: 99%

Spin Waves Transmission via a Molecular Junction Connecting Two Quasi-2d Heisenberg Ferromagnets

2009

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A theoretical investigation of spin wave dynamics and scattering at a molecular junction between two Heisenberg ferromagnets is presented. The model system consists of two ferromagnetic ultrathin films with equal thickness of three atomic layers, joined together by a magnetic molecule. No electronic effects are considered, but local changes in the magnetic exchange field are assumed to be dominant. The mathematical framework of the matching method is used with nearest neighbor magnetic exchange interactions, to analyze both the spin fluctuation dynamics and the spin wave scattering phenomena at the junction boundary. The coherent reflection and transmission probabilities and the conductance of spin waves incident from the interior of the films onto the boundary are calculated in accordance with the Landauer-Büttiker formalism, and numerical results are presented for representative sets of system parameters for a large range of scattering frequencies. The scattered spectra show interesting sharp features, with associated Fano resonances, as a function of scattering frequencies, system parameters, and spin wave incidence angle. Moreover, a frequency selective conductance of the spin waves via Fano resonances can be obtained by an appropriate choice of the spin wave incident angle and system parameters.

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