Megj: Azokat a cikkeket, amik mar mas adatbazisban szerepelnek,
ide hivatkozni!!! (Itt csak 1999-es Fe/Cr cikkek vannak) a keresokerdes:
MULTILAYERS AND COUPLING AND FE AND CR volt)
SCI CDE with Abstracts (Jan 99 - Jul 99) (D4.0)
Title: Hydrogen-Induced Changes of Magnetic-Properties of Iron-Chromium Multilayers Authors: Kandasamy-K Masuda-M Hayashi-Y Full source: JOURNAL OF ALLOYS AND COMPOUNDS 1999, Vol 288, Iss 1-2, pp 13-24 Abstract: The influence of hydrogen implantation on the structural, magnetic and electrical properties of iron-chromium (Fe/Cr) multilayers was investigated. Hydrogen implantation increases the bi-layer thickness, lattice constant, remanent magnetic moment and saturation resistivity but reduces the saturation magnetic field, magnetoresistance and the giant magnetoresistance of multilayers. Changes in the saturation magnetic moments of multilayers after hydrogen implantation are also observed. (C) 1999 Elsevier Science S.A. All rights reserved.
A cikkben hivatkozott cikkek (trilayeresek persze):
The magnitude of the bilinear and biquadratic interlayer coupling strengths between Fe layers separated by Cr spacer layers is investigated by means of Brillouin light scattering, magneto-optic Kerr rotation, and magnetoresistance techniques. A data analysis scheme, which treats all three data sets on an equal footing, yields self-consistent anisotropy and interlayer coupling parameters extracted independently from the three techniques. The values of the bilinear and biquadratic coupling strengths are compared for simultaneously grown (211) and (100) Fe/Cr samples. The approach not only provides reliable values for the coupling strengths but also highlights the complementarity of these techniques in uniquely determining the magnetic parameters.
Ennek a cikknek a hivatkozasai: (kesobb a ra hivatkozokat is kigyujteni az adatbazisbol!)
Abstract: Results are reported of a detailed study of static and dynamic responses in symmetric systems consisting of two ferromagnetic films separated by a nonferromagnetic spacer layer. A comparison is made with experimental results for two systems grown by sputter deposition in an UHV chamber, namely, NiFe/Cu/NiFe and Fe/Cr/Fe. First, we present model calculations where the coupling between the magnetic films through magnetic dipolar, bilinear, and biquadratic exchange interactions are fully taken into account, together with surface, in-plane uniaxial, and cubic anisotropies. An analytical expression is given that can readily be used to consistently interpret magnetoresistance, magneto-optical Kerr effect, ferromagnetic resonance, and Brillouin light scattering (BLS) data in such trilayers. Application of the results to BLS data in Ni81Fe19(d)/Cu(25 Å)Ni81Fe19(d), with d = 200 and 300 Å, shows that it is essential to treat the dipolar interaction adequately in moderately thick systems. The results are also applied to interpret very interesting data in Fe(40 Å)/Cr(s)/Fe(40 Å), with 5 Å < s < 35 Å, investigated by the four techniques mentioned above, at room temperature. It is shown that consistent values for all magnetic parameters can be extracted from the data with a theory that treats both static and dynamic responses on equal footing.
Abstract: Many experiments have verified the presence of a spin-density wave (SDW) within the Cr spacer of Fe/Cr multilayers and wedges. We review the recently proposed interlayer magnetic coupling mediated by a SDW. Unlike previously proposed mechanisms, this magnetic coupling is strongly temperature-dependent. Depending on the temperature and the number N of Cr monolayers (ML), the SDW may be either commensurate (C) or incommensurate (I) with the BCC Cr lattice. (C) 1999 Elsevier Science B.V. All rights reserved.
Abstract: Meaningful tests of theoretical predictions of magnetic multilayer properties require the fabrication of multilayers with nearly the same atomic scale precision as the theoretical models. Multilayers grown epitaxially on single-crystal Fe whisker substrates come very close to this ideal standard. We have investigated the growth, magnetic structure, and exchange coupling of Fe/(Ag, Au, Cr, Mn, V, Cu, or Al)/Fe (1 1 0) whisker structures primarily using reflection high-energy electron diffraction (RHEED) and scanning electron microscopy with polarization analysis (SEMPA), and in some systems, confocal magneto-optic Kerr effect (MOKE) microscopy. In eases of nearly layer-by-layer growth, the measured oscillatory coupling periods and strengths agree well with theoretical predictions. For rougher growth, less predictable non-collinear coupling is generally observed. (C) 1999 Elsevier Science B.V. All rights reserved.
Abstract: The spectrum of excitations in [Fe/Cr](n) structures with a non-collinear magnetic ordering was studied by means of the FMR technique. The measurements were carried out at room temperature in the frequency range of 9.5-37 GHz with both static and microwave magnetic fields lying in the film plane. Along with the acoustic FMR mode several additional modes were observed in the longitudinal pumping configuration. The resonance spectrum of an infinite magnetic superlattice was calculated analytically on the basis of the biquadratic exchange coupling model. Both cases were considered: external magnetic field H parallel and perpendicular to the film plane. It was shown that the observed additional FMR modes correspond to the excitation of standing spin waves with wave vectors perpendicular to the superlattice plane. (C) 1999 Elsevier Science B.V. All rights reserved.
Abstract: A first-principles electronic structure calculation for Fe/Cr multilayers is presented, where a spin-density-wave order in the Cr layer is taken into account in addition to an antiferromagnetic one. The interlayer magnetic coupling between ferromagnetic Fe layers is investigated, and oscillation of the coupling with a two-monolayer period of the spacer thickness of the Cr layer is illustrated. The appearance of the spin-density-wave order in the Cr layer is furthermore demonstrated. (C) 1999 Elsevier Science B.V. All rights reserved.
Abstract: Several recent experiments have detected a spin-density wave (SDW) within the Cr spacer of Fe/Cr multilayers and wedges. We use two simple models to predict the behavior of a collinear SDW within an Fe/Cr/Fe trilayer. Both models combine assumed boundary conditions at the Fe-Cr interfaces with the free energy of the Cr spacer. Depending on the temperature and the number N of Cr monolayers, the SDW may be either commensurate (C) or incommensurate (I) with the bcc Cr lattice. Model I assumes that the Fe-Cr interface is perfect and that the Fe-Cr interaction is antiferromagnetic. Consequently, the I SDW antinodes lie near the Fe-Cr interfaces. With increasing temperature, the Cr spacer undergoes a series of transitions between I SDW phases with different numbers n of nodes. If the I SDW has n = m nodes at T = 0, then it increases by one at each phase transition from m to m-1 to m-2 up to the C phase with n = 0 above T-IC(N). For a fixed temperature, the magnetic coupling across the Cr spacer undergoes a phase slip whenever n changes by one. In the limit N--> infinity, T-IC(N) is independent of the Fe-Cr coupling strength. We find that T-IC(infinity) is always larger than the bulk Neel transition temperature and increases with the strain on the Cr spacer. These results explain the very high IC transition temperature of about 600 K extrapolated from measurements on Fe/Cr/Fe wedges. Model II assumes that the I SDW nodes lie precisely at the Fe-Cr interfaces. This condition may be enforced by the interfacial roughness of sputtered Fe/Cr multilayers. As a result, the C phase is never stable and the transition temperature T-N(N) takes on a seesaw pattern as n greater than or equal to 2 increases with thickness. In agreement with measurements on both sputtered and epitaxially grown multilayers, model II predicts the I phase to be unstable above the bulk Neel temperature. Model II also predicts that the I SDW may undergo a single phase transition from n = m to m-1 before disappearing above TN(N). This behavior has recently been confirmed by neutron-scattering measurements on CrMn/Cr multilayers. While model I very successfully predicts the behavior of Fe/Cr/Fe wedges, a refined version of model II describes some properties of sputtered Fe/Cr multilayers. [S0163-1829(99)03021-0].
Abstract: A first-principles electronic-structure calculation for Fe/Cr superlattices is presented, where a spin-density-wave order in the Cr layer is considered in addition to an antiferromagnetic one. The interlayer magnetic coupling between ferromagnetic Fe layers is investigated, and the oscillation of the interlayer magnetic coupling with a two-monolayer period of the spacer thickness of the Cr layer is illustrated. The appearance of the spin-density-wave order in the Cr layer, which gives rise to a phase slip of the oscillation. is furthermore demonstrated. [S0163-1829(99)51010-2].
Abstract: The long period oscillation of magnetic coupling through Cr as the spacer layer of especially Fe/Cr magnetic multilayers is examined. It is shown that a reasonable empirical adjustment of the d-band position does bring calipers on the N-centered ellipses into agreement with experiment. The lens surface becomes too small and more anisotropic providing further evidence that it is not involved. However, the neck of the jack surface does reach the proper size and so accounts for the photoemission observations. A mechanism of mode coupling to enhance the strength of the long period oscillation is examined and rejected. A thorough examination of the Cr/(V,Mn) alloy spacer data strongly suggests instead a predilection for mode exclusion. [S0163-1829(99)00309-4].