The General Theory of the Dynamic Susceptibility in Thin Ferromagnetic Films

1996

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The dynamic susceptibility of the system with antiferromagnetic coupling between layers is investigated within the framework of the multiband model using the equation of motion with random phase approximation. Calculations are performed in the mixed Bloch-Wannier representation and a general form for χ is found. The susceptibility can be written in terms of two-particle Green's functions expressed in the local coordinate system with the z axis aligned along the local magnetization. The expression depends on an angle between the magnetization direction in a given layer and the crystal axis. Preliminary numerical calculations are performed for two systems: ultrathin Cr film and Fe/Cr multilayer structure. Imaginary part of the susceptibility corresponding to different layers is calculated and spin waves are discussed.

Section: The Dynamic Susceptibilitymentioning

confidence: 61%

Dynamic Susceptibility in Thin Films with Antiferromagnetic Coupling between Layers

1996

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“…Then, the dynamic susceptibility method is used to investigate spin waves, which propagate in the system. The transverse susceptibility of a thin film is calculated within the framework of the random phase approximation (RPA) and the mixed Bloch-Wannier representation is used [9]. Evaluations are performed for various values of a twodimensional wave vector q parallel to the surface.…”

Section: Methods Of Calculationsmentioning

confidence: 99%

Ground-State Properties and Spin Waves in Ultrathin Fe Films Covered with Magnetic and Nonmagnetic Materials

1995

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Properties of ultrathin films consisted of 5 and 7 atomic layers of Fe and covered with magnetic (Co) or nonmagnetic (Cu, Ag) materials are investigated within the framework of the multiband model. Ground-state results consistent with those known from ab initio approaches are obtained. Spin waves are studied in the randk phase approximation with the use of the susceptibility method. Amplitudes and dispersioii relations are calculated. Two acoustic modes with amplitudes enhanced at the interface are found.

“…The thin film dynamic susceptibility is calculated within the framework of the random phase approximation according to the following formula [14]:…”

Section: The Methods Of Calculationmentioning

confidence: 99%

“…X0 denotes here a free-electron susceptibility. Its elements depend strongly on the one-electron Hartree-Fock energies and on the coefficients of expansion of the one-electron wave functions [14]. U corresponds to the effective intraatomic interactions between electrons.…”

Section: The Methods Of Calculationmentioning

confidence: 99%

Temperature Dependence of Magnetization in Transition Metal Ultrathin Films of Various Thicknesses

1991

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Temperature dependence of the local magnetization in the spin-wave regime is calculated within the framework of the multiband model for ultrathin films consisting of 5, 7 and 9 monolayers. The temperature range in which the calculated results can be fitted to the Bloch T 3 /2 law is found in all cases. The Bloch coefficient Bay corresponding to temperature dependence of the average film magnetization is found to be proportional to 1/D, where D is the thickness of the film. The spatial distribution of the local magnetization is obtained. The Bloch coefficient corresponding to the surface layer appears to be greater than the one corresponding to the central layer, namely Bss > B c The ratio BS/Bc is increasing with an increase of the film thickness. The calculated results are well consistent with experimental ones obtained for ultrathin films of various thicknesses.