Ferromagnetic resonance (FMR) is performed together with superconducting auantum interference device and Faraday magnetometry to investigate the magnetic anisotropy of epitaxial bcc Fe(001) films on Ag(001) and Cr(001). The Fe/Ag(001) and Fe/Cr(001) layers as well as corresponding wedge structures were grown by molecular-beam epitaxy. On these samples the following investigations were done. Firstly the temperature dependence of the surface anisotropy of the Fe/Ag system was determined. To achieve high precise values of the surface anisotropy a locally resolved FMR techniaue was applied to an Fe wedge film coated in Ag layers. Secondly the influence of strong deformation of the Fe layer on the magnetic properties was investigated by high-dose Fe-ion implantation in thermally immiscible Fe/Ag(001) layer structures. FMR measurements have shown a pronounced tetragonal symmetry of the anisotropy, which can be precisely controlled by implantation conditions. Thirdly in Fe/Cr single-crystal layers the magnetic parameters of the Fe films show an anomalous temperature behaviour for a distinct Cr thickness range that can be related to the spin-flip transition. The transition temperature decreases continuously with decreasing Cr Jhickness, ceasing in a suppression of the spin flip for Cr thicknesses below 60 Å. Below the transition temperature an increase in the dynamie contribution to the FMR linewidth oceurs which depends on the Cr thickness. The temperature variation in the dynamie line broadening is explained by a band theoretical description which agrees qualitatively with the temperature variation in the magnetic Fe moment.

High dose Fe-ion-implantation induce in the thermally immiscible Ag/Fe (5–20nm)/Ag-(001)-layer-system a strong tetragonal distortion of the Fe-film. For doses less than 1016cm−2 ferromagnetic resonance studies reveal a reduction of the volume magnetic anisotropy constants and a strong increase of the effective surface anisotropy constants. Annealing at 450–600K leads to a relaxation of the magnetic properties indicating the effects of ion implantation on the magnetic properties are caused by atomic intermixing of Ag in the Fe-layer and Fe in the Ag-layer due to ion beam mixing.

In the thermally immiscible Ag/Fe (5–20 nm)/Ag-(001)-multilayer-structure ion beam mixing of the layers induces a strong tetragonal distortion of the Fe-layer. The induced changes of the magnetic properties were determined by the ferromagnetic resonance (FMR) and Faraday magnetometry (FM) methods. For high dose irradiated samples of 1016cm−2 a tetragonal symmetry of the magnetic anisotropy fields was observed. An influence of the ion beam mixing on the saturation magnetisation of the Fe-layer was not detected. Annealing of the samples shows a recovery of the magnetic properties at 450–600 K indicating the influences on the magnetic properties are mainly caused by induced atomic intermixing of Ag in the Fe-layer and Fe in the Ag-layer.

High dose Fe-ion-implantation induce in the thermally immiscible Ag/Fe (5-20 nm)/Ag-(0 0 1)-layer-system a strong tetragonal distortion of the Fe-film. For doses less than 10(16) cm(-2) ferromagnetic resonance studies reveal a reduction of the volume magnetic anisotropy constants and a strong increase of the effective surface anisotropy constants. Annealing at 450-600 K leads to a relaxation of the magnetic properties indicating the effects of ion implantation on the magnetic properties are caused by atomic intermixing of Ag in the Fe-layer and Fe in the Ag-layer due to ion beam mixing. (C) 1999 Elsevier Science B.V. All rights reserved.

In the thermally immiscible Ag/Fe (5-20 nm)/Ag-(001)-multilayer-structure ion beam mixing of the layers induces a strong tetragonal distortion of the Fe-layer. The induced changes of the magnetic properties were determined by the ferromagnetic resonance (FMR) and Faraday magnetometry (FM) methods, For high dose irradiated samples of 10(16) cm(-2) a tetragonal symmetry of the magnetic anisotropy fields was observed. An influence of the ion beam mixing on the saturation magnetisation of the Fe-layer was not detected. Annealing of the samples shows a recovery of the magnetic properties at 450-600 K indicating the influences on the magnetic propel ties are mainly caused by induced atomic intermixing of Ag in the Fe-layer and Fe in the Ag-layer. (C) 1999 Elsevier Science B.V. All rights reserved.

The change of the thickness dependent anisotropies of high dose ion-implanted Ag/Fe/Ag-(001)-layers were studied by ferromagnetic resonance. The experimental results are discussed within the frame of a phenomenological model considering implantation induced lattice misfit strains, which are caused by the reduction of the Ag lattice parameter by interface mixed Fe. With additional structural data from x-ray-diffraction the magnetoelastic constant B1 is determined, which agrees well with the bulk value.

Ion beam induced modifications of the magnetic properties of thin ferromagnetic films were investigated with the sensitive ferromagnetic resonance. The effects of compositional changes were studied by high dose Ni-implantations into polycrystalline Fe20Ni80-alloy-films, which lead mainly to a reduction of the magnetization due to Ni-enrichment. On the other hand the influences of radiation damages and ion beam mixing were investigated by Fe-irradiations in epitaxial Ag/Fe/Ag-layers. The irradiations result in a decrease of the uniaxial-perpendicular- and of the magnetocrystalline-anisotropy constant, which is attributed to strain relaxation. At high fluences of 1016 cm-2 we observed a change of the magnetocrystalline anisotropy from cubic towards a tetragonal symmetry

High fluence implantation of 95-keV Fe-ion in epitaxial Ag/Fe 200 Å/Ag-(001)-multilayers were performed to induce structural modifications. The correlation between structural quality and magnetic properties was investigated by measurements with ferromagnetic resonance (FMR) and out-of-plane x-ray-diffraction techniques (XRD). The FMR results show for fluences up to 1015 cm−2 a decrease of the crystalline- and perpendicular-uniaxial anisotropies, which are attributed to strain relaxation due to the ion-irradiation detected with XRD. From these results the magnetoelastic coefficient B1 is determined to −3×106 J/m3. At higher fluences of 1016 cm−2 we observe a strong reduction of the perpendicular-uniaxial anisotropy and a change of the crystalline anisotropy from cubic towards that of a tetragonal symmetry. Further, increasing fluences lead to a lattice widening above the Fe-bulk value and an increase of the interface roughness.

Ion beam mixing in epitaxial Ag/Fe/Ag-(001)-layers by 95 keV-Fe-ions at room temperature has been investigated by means of ferromagnetic resonance (FMR) and out-of-plane x-ray-diffraction (XRD). The XRD-data show for fluences less than 10(15) cm(-2) a strain relaxation of the Fe-layer and interface roughness of 1-3 monolayers. The influence on the magnetic parameters can be well described by a magnetoelastic effect due to the strain relaxation indicating rearrangements and demixing at the interfaces. At a fluence of 10(16) cm(-2) we observe a strong reduction of the perpendicular-uniaxial-anisotropy and a change of the crystalline-anisotropy from cubic towards that of a tetragonal symmetry. Simultaneously a lattice widening above the Fe-bulk value and an increase of the interface roughness occur.

For Nickel, a candidate material for pump limiter plates in Tokamak reactors, the effects of He-ion implantation on the thermal properties have been measured by means of IR detection of thermal waves. For ion energies of 25 - 100 KeV considerably reduced thermal properties have been found just at the surface, for ion energies of 1 - 3 MeV the reduced thermal properties are mainly deeper below the surface.

For nickel, a candidate surface material for pump limiters in Tokamak reactors, the effects of He ion implantation on the thermal properties have been analysed by means of thermal wave measurements based on IR detection

The effects of He irradiation on the thermal properties of polycrystalline nickel and graphite have been measured by means of thermal waves. Both the amplitude and the phase of the thermal waves have been interpreted in the frame of a two-layer model, where the changes of the thermal properties of the first layer serve to characterize the effects of irradiation and erosion.

Permalloy (Py) films in the thickness range 150 to 250 nm have been irradiated with 95 keV Ni ions at doses up to 5 × 1016 cm−2. The effect of irradiation on the surface and bulk magnetic properties have been investigated by ferromagnetic resonance (FMR). In these samples the ion implantation changes the effective magnetization and modifies the surface anisotropy constants values.

Spin-wave resonance (SWR) has been applied to investigate the influence of Ni-ion implantation onto the magnetic properties of Permalloy films. The implantation has been carried out at room temperature with different doses at Ni-ion energies of 95 keV. In films of 30–60 nm thicknesses, which are thin compared to the implantation range, with increasing dose the uniform mode is shifted to higher resonance fields in the parallel configuration. In the perpendicular configuration one obtains a shift to lower fields. The corresponding variation of the effective magnetization as a function of the implantation dose could be reproduced by assuming a change of the average volume magnetization. In thicker films (150–250 nm) standing spin waves are excited which are only slightly modified by implantation compared to the as-prepared samples. The observed effects can be attributed to changes of the surface anisotropy.