Ion beam induced surface and interface engineering

Surface modifications caused by a swift heavy ion irradiation on a crystalline p-type silicon crystal have been reported. ∼100 MeV Si 7+ ions from a 15UD Pelletron source has been employed with varying fluence of 10 12 and 10 13 ions cm −2 . Atomic force microscopy has been extensively used to study these surface modifications. Significant observation includes the evidence for a plastic flow upon irradiation. Attempts have been made to explain the results on the basis of radiation-induced amorphization followed by recrystallization. The observation confirms the occurrence of these types of effects in such irradiations and is in line with the models based on thermal spike approach.

Evidence of plastic flow and recrystallization phenomena in swift (∼100 MeV) Si7+ ion irradiated silicon

Instead of static entropy we assert that the Kolmogorov complexity of a static structure such as a solid is the proper measure of disorder (or chaoticity). A static structure in a surrounding perfectly-random universe acts as an interfering entity which introduces local disruption in randomness. This is modeled by a selection rule $R$ which selects a subsequence of the random input sequence that hits the structure. Through the inequality that relates stochasticity and chaoticity of random binary sequences we maintain that Lin's notion of stability corresponds to the stability of the frequency of 1s in the selected subsequence. This explains why more complex static structures are less stable. Lin's third law is represented as the inevitable change that static structure undergo towards conforming to the universe's perfect randomness.

/pdf/an-algorithmic-complexity-interpretation-of-lin-s-third-law-w204uco517.pdf

An algorithmic complexity interpretation of Lin's third law of information theory

Instead of static entropy we assert that the Kolmogorov complexity of a static structure such as a solid is the proper measure of disorder (or chaoticity). A static struc- ture in a surrounding perfectly-random universe acts as an interfering entity which introduces local disruption in randomness. This is modeled by a selection rule R which selects a subse- quence of the random input sequence that hits the structure. Through the inequality that relates stochasticity and chaoticity of random binary sequences we maintain that Lin's notion of sta- bility corresponds to the stability of the frequency of 1s in the selected subsequence. This explains why more complex static structures are less stable. Lin's third law is represented as the inevitable change that static structure undergo towards conforming to the universe's perfect randomness.

/pdf/an-algorithmic-complexity-interpretation-of-lin-s-third-law-2384jwcrtm.pdf

An Algorithmic Complexity Interpretation of Lin's Third Law of Information Theory

Irradiation of pure gallium by Xe ions (3.5 GeV)

Transient response of a 2500 A thick superconducting Nb film to the impact of a single 129Xe50+ ion of total energy 3.2 GeV, transferring about 2.4 keV/A of electronic excitation energy, was observed by means of a superconductor-insulator-superconductor tunnel junction attached to the film some distance away from the impact point. The response had rise time of less than 150 ps (resolution limit of the electronic detection system) and decay time varying from 2 to 1.3 ns as function of temperature. Main experimental features, if not finer details, are in good agreement with Rothwarf and Taylor theory of nonequilibrium processes in superconductors.

Observation of Transient Response of Nb Superconducting Thin Film to a Single-Heavy-Ion Impact

We have studied the relation between clusterization in the flux of a substance and the thickness of deposited films obtained by the magnetron and pulsed laser sputtering of La0.7Sr0.3MnO3 and YBa2Cu3O7 − δ targets, respectively. No cluster formation has been observed in the case of magnetron sputtering, which is explained by a low concentration of atoms (ions) in the sputtered material flux. In accordance with calculations for the flux of non-interacting atoms, the deposited film thickness (h) exhibits exponential decrease with increasing distance (L) from the target. In the case of pulsed laser sputtering, for which the concentration of sputtered substance in the plasma is four orders of magnitude higher, the h(L) curve sharply deviates from the calculated dependence for the distances L > 6.2 cm, which is explained by the onset of intense clusterization in the laser plasma flux.

H. Bielska-Lewandowska

Papers

Observation of Transient Response of Nb Superconducting Thin Film to a Single-Heavy-Ion Impact

Effect of flux clusterization on the thickness of films deposited by magnetron and pulsed laser sputtering of metal oxides