[en] Evaporated Al-films were irradiated at low temperature (<7 K) with self-ions. The influence of oxygen present in the layers on the radiation damage and on the superconducting transition temperature Tsub(C) was investigated. (orig.)

[en] In applications of high-T_c-Superconductivity (HTSC) thin films play a major role. Thus it was the aim of the project, which is reported on, to develop and optimize deposition processes of HTSC-films on technologically-relevant substrates. In addition, the influence of ion irradiation on the superconducting properties were studied. Accompanying work has been performed to develop contact-free quantitative techniques to characterize especially thin films. (orig.)

[en] Gold nanoparticles are deposited on top of atomically flat SrTiO₃(0 0 1) substrates either by exploiting the self-organization of Au-loaded inverse diblock-copolymer micelles or by dewettting thin (3 nm) Au films at 700 deg. C. The resulting nanoparticles were overgrown by YBaCuO films prepared by off-axis cylindrical magnetron sputtering at 730 deg. C, the standard conditions to grow c-axis-oriented epitaxial films. In the present case, no influence of the Au particles on the structural (orientation, lattice parameter, rocking angle) or superconducting properties could be observed. Applying high resolution transmission electron microscopy, it turned out that the Au nanoparticles under the above conditions were 'lifted' by the YBaCuO film, i.e. one obtains the surprising result that the deposition of a YBaCuO film on top of Au nanoparticles on SrTiO₃(0 0 1) leads to Au nanoparticles on top of the YBaCuO film immediately explaining why the overall structural and superconducting properties remain unaffected

No abstract available

[en] Ion beam techniques can be used to produce amorphous metallic systems either by implanting a glass-forming species into a pre-existing crystalline metal or by irradiating a crystalline compound with inert ions. Ion beam mixing experiments in which a crystalline multilayered structure is bombarded with inert ions are related to the latter method. Examples of these different methods are given and empirical rules, which may help to predict whether a given system can be forced into an amorphous phase by ion beam techniques, are discussed. Special emphasis is placed on the question of whether energy spikes are necessary for amorphization. In this context, new results of low temperature ion irradiation experiments on Al₂Au are reported. (Auth.)

[en] Theoretical predictions make the Bi_xPd_1-x system a promising candidate for studying the possibility of amorphization by an enforced extension of the solubility into a metastable regime. By quench-condensation of Bi₃₀Pd₇₀, the existence of a previously unknown amorphous (a-) phase is proven, which above 520 K crystallizes into the monoclinic Bi₂Pd₅ phase. Ar⁺-irradiation of this crystalline phase at low temperatures leads back into the a-phase in accordance with a general amorphization rule. Experimentally, this behaviour is demonstrated by applying in situ resistance measurements and ex situ XRD. A surprising result is found for supersaturated Pd₇₀Bi₃₀ solid solutions, which can be prepared by exploiting interface reactions in Pd/Bi multilayers. Ion irradiation performed on these cubic metastable solid solutions under exactly the same conditions as above, result only in a segregation of the surplus Bi towards the equilibrium solubility limit. No irradiation induced amorphization can be obtained starting with a stable or metastable cubic solid solution

[en] Sputtered NbN-films are ion irradiated at 295 K with 350 keV Ne⁺-ions thereby producing radiation damage, and the corresponding changes of the temperature-dependent electrical resistivity and the thermopower are determined within 16 K ≤ T ≤ 295 K for different ion fluences. Regarding the bombarded film as a binary mixture of grains with defect densities below or above a certain threshold value, the above measurements allow a binary mixture model for the thermopower to be tested. Excellent agreement between theory and experiment is found, though the irradiation-induced resistivity changes do not obey Matthiessen's rule. (author)

No abstract available

[en] Pd films were produced in a long mean free path dc triode system using Kr as sputter gas ( p_Kr = 1 mTorr) and with simultaneous ion bombardment of the growing Pd film. The resulting film properties are related to the energy E_n delivered by the bombarding Kr ions to the growing film per arriving sputtered Pd atom. Systematic changes of the Kr concentration, the lattice parameter, strain, grain size, preferential orientation, and residual resistivity are observed as a function of E_n. Analysis of the data suggests that, in addition to a possible direct influence of the incorporated Kr, defects produced by the ion bombardment are causing these property changes. This is confirmed by preliminary TEM results revealing a high density of dislocations

No abstract available