G. Gladyszewski

Ion-assisted deposition of Ag(001)/Fe(001) multilayers: interface roughness

Abstract We report on the growth and structure of Ag/Fe superlattices grown on MgO(001) substrates studied by X-ray diffraction (XRD) and atomic force microscopy (AFM). Ion-assisted deposition (IAD) was used to modify the multilayer interfaces during the growth process. The structure characterization was performed using symmetric and asymmetric XRD techniques. The Ag(001)〈100〉//Fe(001)〈110〉//MgO(001)〈100〉 growth was obtained using an ion-beam sputtering technique. The XRD results were interpreted using the model of nonideal superlattice structure based on a Monte-Carlo simulation. The surface roughness was characterized using AFM. The decrease of the r.m.s. roughness for the samples grown in IAD mode in comparison with samples grown without ion assistance was evidenced.

On the Fe thickness dependence of the giant magnetoresistance in epitaxial Fe/Cr superlattices

Abstract We analysed the transport properties of Fe/Cr(100) superlattices as a function of the Fe thickness. We find two magnetic inactive atomic layers and interpret the magnetoresistance with the quasi-classical formalism based on the Boltzmann kinetic equation.

Structure of Ag/Fe superlattices probed at different length scales

Abstract We report on the growth and structure of Ag(001)/Fe(001) superlattices studied in situ by reflection high-energy electron diffraction (RHEED) and ex situ by Rutherford backscattering and channeling spectroscopy (RBS/C), X-ray diffraction (XRD) and atomic force microscopy (AFM). These complementary characterization methods have been compared and applied to a detailed investigation of the epitaxial quality and the interface roughness. The apparent inconsistency in the results is explained by the difference in length scale probed by the four characterization techniques.

Structural and magnetic properties of Fe/Cr and Fe/Ag multilayers

Abstract The structural and magnetic properties of Fe/Cr and Fe/Ag magnetic superlattices are discussed. The presence of antiferromagnetic coupling in Fe/Cr superlattices was clearly established, whereas Fe/Ag superlattices do not show antiferromagnetic coupling in their as-prepared state. Thermal annealing and ion irradiation lead to an increase of the magnetoresistance due to the formation of a granular FeAg alloy and a Kondo system, respectively.

Relation between structural and physical properties in magnetic and superconducting superlattices

The physical properties of superlattices are strongly affected by the chemical and physical properties of the individual layers and by the superlattice structure. In this paper the relationship between structure and properties will be illustrated by the giant magnetoresistance (GMR) effect, as well as the dimensional transitions and pinning mechanisms in respectively magnetic and superconducting superlattices. In the first example we will analyse the effect of the sample structure and interface quality on the GMR of polycrystalline and epitaxial Fe/Cr superlattices grown by molecular beam epitaxy. Secondly, the effect of thermal annealing and ion irradiation on the electrical and magnetic properties of Ag/Fe multilayers is discussed. In a third example, the influence of a very thin Fe interlayer on the coupling phenomena in Fe/Nb multilayers is analysed. Finally, it will be shown that an additional lateral modulation (lattice of submicron holes) in Pb/Ge multilayers substantially changes the critical superconducting parameters.

Effect of ion irradiation on the structure of AuNi multilayers

Abstract The effect of 340 keV Kr ion irradiation on the structure of polycrystalline sputtered Au Ni superlattices was studied. Different structural modifications are observed depending on the irradiation dose range. An ion-induced relaxation of the compressive stresses initially present in the layers is observed even after very small doses (

Modification of structure, electric and magnetic properties of epitaxially grown Ag(001)/Fe(001) superlattices

Abstract The influence of ion irradiation and annealing on the structure, electrical and magnetic properties of Ag(001)[100]‖Fe(001)[110] superlattices are investigated. The changes of the structure are characterized by X-ray diffraction. The temperature and field dependencies of the resistivity are measured to find a link between the structure modification and magnetoresistance. Both treatments lead to a significant increase of the magnetoresistance.

Effect of ion irradiation on the structure of Au/Ni multilayers

The effect of 340 keV Kr ion irradiation on the structure of polycrystalline sputtered Au/Ni superlattices was studied. Different structural modifications are observed depending on the irradiation dose range. An ion-induced relaxation of the compressive stresses initially present in the layers is observed even after very small doses (<0.5 X 10 -1 dpa). With an increasing dose, a progressive interdiffusion at the interfaces is clearly observed accompanied by a reduction of the structural disorder and by an improvement of the texture. Finally, at higher doses (8 dpa), a complete mixing is achieved leading to the formation of a metastable fcc polycrystalline solid solution exhibiting a strong (111) texture.

Epitaxially grown superlattices

Abstract Results of the structure characterization of Ag Fe superlattices are presented. Two methods were combined in the investigations: atomic force microscopy and X-ray diffraction (XRD). The studies show that Ag(001) Fe(001) superlattices are epitaxial, and their structural quality is unusually high as for metallic superlattices. XRD profiles are interpreted using two different computer programs, SUPREX and IM-SL.

Epitaxially grown Ag(001)Fe(001) superlattices

Abstract Results of the structure characterization of Ag Fe superlattices are presented. Two methods were combined in the investigations: atomic force microscopy and X-ray diffraction (XRD). The studies show that Ag(001) Fe(001) superlattices are epitaxial, and their structural quality is unusually high as for metallic superlattices. XRD profiles are interpreted using two different computer programs, SUPREX and IM-SL.