Influence of atomic ordering on the spin waves in Ni<sub>0.75</sub>Fe<sub>0.25</sub>alloy

Mikke, K.; Jankowska, Joanna; Osetek, Z.; Modrzejewski, A.

doi:10.1088/0305-4608/7/7/010

Cited by 8 publications

(3 citation statements)

References 5 publications

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“…Because we did not obtain really converged results for the optical branches, Fig. 4 27 that D increases with increasing degree of order, attaining a value of 420 meVÅ 2 for the best ordered samples. Altogether, we think that the agreement between theory and experiment is quite satisfactory.…”

Section: Rapid Communicationsmentioning

confidence: 89%

Fastab initiomethods for the calculation of adiabatic spin wave spectra in complex systems

Grotheer¹,

Ederer²,

Fähnle³

2001

Phys. Rev. B

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The interpretation of the physics of magnets with reduced dimensionality often requires information on the spin wave excitations at arbitrary wavelengths which is generally hard to obtain experimentally. Two powerful methods for the ab initio calculation of adiabatic spin-wave spectra are introduced, a frozen-magnon-torque method for systems with large exchange fields and a transverse-susceptibility method which may be used also for materials with smaller exchange fields. The efficiency of both methods results from the fact that the number of calculations required to obtain the spin-wave spectrum scales linearly with the number of basis atoms in the unit cell. Results are given for Fe, Co, Ni, permalloy Ni 3 Fe, and CoFe, materials which are often used for thin-film technologies. DOI: 10.1103/PhysRevB.63.100401 PACS number͑s͒: 75.30.Ds, 71.15.Ap, 71.15.Mb In recent years magnetism in reduced dimensionality has become extremely important because of the very rapid development of thin-film technologies for basic research and for applications in magnetotransport. Thereby, spin excitations like single-particle Stoner excitations or collective spinwave excitations 1 play a central role for thermostatic phenomena, but also for the transport phenomena because the spin-dependence of the inelastic mean free path of an excited hot electron is determined by spin-flip exchange scattering at these excitations. 2,3 A quantitative analysis of the various phenomena requires information about the spin-wave spectra which is often difficult to obtain experimentally. One example is the spin-dependent transport of hot electrons in a spin-valve transistor where in the ''bulk'' of the metallic components spin-flip exchange scattering at spin waves of all wavelengths occurs. Because the energies of shortwavelength spin waves in 3d transition metals are very large, it is difficult and costly to investigate the bulk spin wave spectra of various 3d magnets used in the devices by neutron-scattering experiments. A second example is the generation of magnons by hot electrons at the interfaces between the insulating barrier and the magnetic electrodes of magnetic tunnel junctions which is responsible for the reduction of the magnetoresistance. 4 Because the magnon spectrum at such an interface is hardly accessible by experiments, the quantitative analysis of the data so far must manage with a simple modelling of the spin-wave spectra by a Debye model. 4 Finally, the short-wavelength spin waves at surfaces or in ultrathin magnetic films of few magnetic monolayers contribute to the spin polarized electron energy loss spectrum. 3 Whereas low-energy spin waves in ultrathin films can be studied by ferromagnetic resonance 5 or by Brillouin scattering experiments, 6 the direct experimental determination of the short-wavelength spectrum is again difficult.From the above discussion it becomes obvious that a theoretical determination of spin wave spectra would be extremely helpful for a quantitative analysis of experimental data, especially for comp...

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Section: Rapid Communicationsmentioning

confidence: 89%

Fastab initiomethods for the calculation of adiabatic spin wave spectra in complex systems

Grotheer¹,

Ederer²,

Fähnle³

2001

Phys. Rev. B

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Section: Introductionmentioning

confidence: 99%

“…[3] The random site disorder plays a strong role in the reduction of collinearity, evidenced in the 30% reduction of exchange stiffness for x = 0.75 (Ni 3 Fe) upon an order-disorder transformation. [4] In Ni 81 Fe 19 (permalloy,) total energy calculations predict a 1-2 • average angle of moment noncollinearity at T=0. [5] The magnetization dynamics of Ni 81 Fe 19 have been studied more intensively than those of any other alloy.…”

Section: Introductionmentioning

confidence: 99%

Precessional dynamics of elemental moments in a ferromagnetic alloy

et al. 2004

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We demonstrate an element-specific measurement of magnetization precession in a metallic ferromagnetic alloy, separating Ni and Fe moment motion in Ni 81 Fe 19 . Pump-probe X-ray magnetic circular dichroism (XMCD), synchronized with short magnetic field pulses, is used to measure free magnetization oscillations up to 2.6 GHz with elemental specificity and a rotational resolution of < 2 • . Magnetic moments residing on Ni sites and Fe sites in a Ni 81 Fe 19 (50nm) thin film are found to precess together at all frequencies, coupled in phase within instrumental resolution of 90 ps.

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Effects of Order on the Electronic Structure of Ni₃Fe

Lipiński

1983

Physica Status Solidi (b)

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The electronic densities of states for partially ordered Ni,Fe are calculated within the framework of the Hartree-Fock and coherent potential approximations. The four-sublattices Hubbard model with an ansatz simplifying the hopping part of the Hamiltonian is used.Im Rahmen der Hartree-Fock-Ngherung und der CPA werden die Zustandsdichten fur teilweise geordnetes Ni,Fe berechnet. Ein Vieruntergitter-Hubbard-Model1 mit einem Ansatz, der den Hoppingteil dcs Hamiltonians vereinfacht, wird bcnutzt.

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Influence of atomic ordering on the spin waves in Ni_0.75Fe_0.25alloy

Cited by 8 publications

References 5 publications

Fastab initiomethods for the calculation of adiabatic spin wave spectra in complex systems

Fastab initiomethods for the calculation of adiabatic spin wave spectra in complex systems

Precessional dynamics of elemental moments in a ferromagnetic alloy

Effects of Order on the Electronic Structure of Ni₃Fe

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Influence of atomic ordering on the spin waves in Ni0.75Fe0.25alloy

Cited by 8 publications

References 5 publications

Fastab initiomethods for the calculation of adiabatic spin wave spectra in complex systems

Fastab initiomethods for the calculation of adiabatic spin wave spectra in complex systems

Precessional dynamics of elemental moments in a ferromagnetic alloy

Effects of Order on the Electronic Structure of Ni3Fe

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Product

Resources

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Influence of atomic ordering on the spin waves in Ni_0.75Fe_0.25alloy

Effects of Order on the Electronic Structure of Ni₃Fe