A. Boufelfel

Brillouin scattering from collective spin waves in magnetic superlattices (invited)

We report on the observation and the analysis of collective magnetostatic spin‐wave excitations in magnetic superlattices. The influence of interface anisotropies, which can become dominant for small modulation wavelengths, is discussed. For the system Fe/Pd we show that Brillouin spectroscopy experiments in combination with the measurement of the saturation magnetization by a SQUID magnetometer give evidence for a magnetic polarization of the Pd spacer layers, as well as for a small negative out‐of‐plane interface anisotropy constant of Ks =−0.15 erg/cm2.

Fe/Pd second-order superlattices

Abstract We report the structural and magnetic properties of a new class of Fe/Pd second-order superlattices, formed by alternating two bilayers with different repeat periods. Chemical and structural characterization were obtained using Rutherford backscattering spectroscopy (RBS) and several x-ray diffraction techniques, respectively. The properties of the collective spin wave spectrum were studied by Brillouin scattering.

Metal-Metal Superlattices

An introduction to metal-metal superlattices is presented, along with a brief review of some of the materials which have been made, and phenomena which have been observed so far. We describe in detail the results of a number of structural characterization techniques applied to these materials, including Bragg θ-2θ x-ray diffraction, transmission and reflection Laue diffraction, wide film Debye-Scherrer diffraction, Rutherford Backscattering Spectroscopy (RBS) and Auger Electron Spectroscopy (AES). Particular emphasis is placed on recent results obtained with Ta/Mo superlattices produced by sputtering techniques.

Collective spin waves in Fe/Pd and Fe/W multilayers

In Fe/Pd and Fe/W multilayers the complete, theoretically predicted band of collective magnetostatic spin‐wave excitations has been observed. Despite the large number of bilayers (49–90) discrete spin‐wave modes have been found in the upper half of the band. For Fe/Pd multilayers the saturation magnetization shows a monotonic reduction of up to 30% with decreasing modulation wavelength (down to 33 A), which is not found in the Fe/W multilayer.

De Haas-Van Alphen effect in quenched platinum

Abstract The Dingle (scattering) temperature in Pt containing vacancies is reported for cyclotron orbits on the electron and open hole sheets of the Fermi surface (FS). The anisotropy of conduction electron scattering due to vacancies is discussed.

Thickness variation effects on X-ray scattering of multilayers

A cosine-squared flux distribution from a disk-shaped source was used to calculate the spatial deposition profiles for films sputtered onto rotating substrates. Depositions were made by a stable and reproducible d.c. sputtering machine and thicknesses measured by Rutherford backscattering spectroscopy to compare with this calculation. The measured and calculated profiles were compared at a fixed value of target-substrate distance. We showed for the first time that the thickness variation is largely responsible for the broadening of the X-ray Bragg peaks at low angles of Fe/Pd multilayers. These results have important implications for the classical interpretation of X-ray scattering from multilayered structures.

Structural and magnetic studies of Fe/W metallic superlattices (abstract)

We have sputter deposited Fe/W superlattices on several types of substrates using magnetically enhanced dc sputtering guns. The deposition rates were controlled to better than 0.3%. We used a 6‐MV Rutherford backscattering facility to determine the chemical composition with 0.5% relative uncertainty. We varied the modulation wavelength from Λ=4.4 to 250 A, keeping the number of atomic layers equal for both materials. Structural characterization was achieved by several x‐ray diffraction techniques. We found that the superlatticestructural coherency breaks down below Λ c =21.5 A, although the multilayered structural periodicity still holds below this value. We used conversion electron Mossbauer spectroscopy to measure the intrinsic hyperfinemagnetic field of the samples at room temperature. The data was fitted with two independent methods which show very good agreement. We observed a decrease in the hyperfine field value as the modulation wavelength Λ decreases, and a disappearance for Λ<Λ c . This effect is interpreted as due to structural strains of the whole superlattice and electronic structure changes at the interfaces.

Structural, electrical, and magnetic properties of Fe/Pd superlattices (abstract)

We have made Fe/Pd superlattices with periodic modulation wavelength Λ ranging from 33.2 to 188.4 A. Long‐range structural coherency is inferred from several x‐ray diffraction techniques. Fe and Pd were found to grow (110) and (111) parallel to the substrate, respectively. The in‐plane electrical resistivity was measured in the range 7.5–300 K by the four‐point probe method. The dependence of the resistivity on Λ will be explained by a model using interfacial scattering of electrons. Room‐temperature magnetic properties of the samples were measured using conversion electron Mossbauer spectroscopy and vibrating sample magnetometry. We found all the samples to be ferromagnetic. Both the intrinsic hyperfine magnetic field and the saturation magnetization show an increase as Λ decreases. We found that both of these physical quantities strongly depend on the number of atomic layers of (110) Fe in Λ. We did not find any induced magnetism in (111) Pd to within the experimental error. We determined the magnetic m...