Der Einfluß der Grenzflächenrauhigkeit auf den Riesenmagnetowiderstandseffekt in epitaktischen Fe/Cr/Fe-Schichten

Epitaxial Fe/Cr/Fe trilayers with varying interface roughness were fabricated using molecular beam epitaxy. They were patterned into stripes to investigate the influence of interface roughness on the giant magnetoresistance (GMR) effect. (001) oriented gold and silver buffer layers on GaAs were used as suhstrates and proved to be a very good choice for monocrystalline growth. During layer growth, single deposited monolayers could be distinguished observing oscillating intensities of the diffraction pattern of high energy electrons (RHEED). This feature was exploited to determine layer thicknesses and to intentionally finish the preparation of a given layer at filled or half filled top atomie layers, corresponding to flauer or rougher surfaces, respectively. An essential condition for the observation of GMR behaviour is the possibility to influence the magnetic configuration of the sample. This was given, for the magnetizations of the iron layers separated by the chromium spacer layer of a suitable thickness were coupled antiferromagnetically and could be aligned parallel by an external magnetic field. In spite of the dominating electrical conductivity of the underlying gold or silver buffer layer, measuring the giant magnetoresistance with the current flowing in the plane of the layers (CIP geometry) revealed possible. In samples with interface roughnesses tailored during preparation, the amplitude of the GMR effect depended on the roughnesses of the interfaces of the fron and chromium layers: With rougher interfaces, the GMR effect was enhanced. In this work, the influence of the interfaces on the GMR effect was examined using well-defined monocrystalline samples with the simplest possible configuration, i. e. trilayers made of two ferromagnetic layers separated by one spacer layer. In former approaches to investigate the rote of the interfaces, multilayered samples (some of them polycrystalline) were used or the interfaces were modified introducing other materials

Metallic-type oscillatory interlayer exchange coupling across an epitaxial FeSi spacer

We study interlayer exchange coupling in epitaxial Fe/Fe0.56Si0.44/Fe trilayers. Iron-silicide spacers with high structural and compositional homogeneity for thicknesses up to 34 Angstrom are grown by coevaporation from two electron-beam sources. The coupling strength oscillates with spacer thickness for temperatures from 20 to 300 K with two antiferromagnetic maxima at 12 and 26 Angstrom, and it clearly increases with decreasing temperature down to 80 K. We conclude that the coupling across ordered Fe1-xSix (x approximate to 0.5) is described by the conventional theory of interlayer coupling across metallic spacers

Spin waves propagation and confinement in conducting films at the micrometer scale

The propagating spin wave spectroscopy (PSWS) technique is applied for the first time to metallic thin film patterns, allowing to measure their magnetostatic wave modes. Using micrometer scale local excitation and detection, we show that magnetostatic surface waves propagate on a distance as long as 40 \un{\mu m} in a continuous permalloy film. In micrometer wide permalloy stripes, we observe both quantized spin wave modes and quasi-saturation modes, well explained by existing models. In addition, low-frequency additional modes were observed which, we suggest, are generated in the magnetically inhomogeneous edge regions

Der Einfluss der Grenzflaechenrauhigkeit auf den Riesenmagnetowiderstandseffekt in epitaktischen Fe/Cr/Fe-Schichten

Epitaxial Fe/Cr/Fe trilayers with varying interface roughness were fabricated using molecular beam epitaxy. They were patterned into stripes to investigate the influence of interface roughness on the giant magnetoresistance (GMR) effect. (001) oriented gold and silver buffer layers on GaAs were used as substrates and proved to be a very good choice for monocrystalline growth. During layer growth, single deposited monolayers could be distinguished observing oscillating intensities of the diffraction pattern of high energy electrons (RHEED). This feature was exploited to determine layer thicknesses and to intentionally finish the preparation of a given layer at filled or half filled top atomic layers, corresponding to flatter or rougher surfaces, respectively. An essential condition for the observation of GMR behaviour is the possibility to influence the magnetic configuration of the sample. This was given, for the magnetizations of the iron layers separated by the chromium spacer layer of a suitable thickness were coupled antiferromagnetically and could be aligned parallel by an external magnetic field. In spite of the dominating electrical conductivity of the underlying gold or silver buffer layer, measuring the giant magnetoresistance with the current flowing in the plane of the layers (CIP geometry) revealed possible. In samples with interface roughnesses tailored during preparation, the amplitude of the GMR effect depended on the roughnesses of the interfaces of the iron and chromium layers: With rougher interfaces, the GMR effect was enhanced. In this work, the influence of the interfaces on the GMR effect was examined using well-defined monocrystalline samples with the simplest possible configuration, i. e. trilayers made of two ferromagnetic layers separated by one spacer layer73 refs.SIGLEAvailable from TIB Hannover: RA 831(3742) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman