Tailoring strain in SrTiO3 compound by low energy He+ irradiation

The ability to generate a change of the lattice parameter in a near-surface layer of a controllable thickness by ion implantation of strontium titanate is reported here using low energy He+ ions. The induced strain follows a distribution within a typical near-surface layer of 200 nm as obtained from structural analysis. Due to clamping effect from the underlying layer, only perpendicular expansion is observed. Maximum distortions up to 5-7% are obtained with no evidence of amorphisation at fluences of 1E16 He+ ions/cm2 and ion energies in the range 10-30 keV.Comment: 11 pages, 4 figures, Accepted for publication in Europhysics Letter (http://iopscience.iop.org/0295-5075

Temperature dependence of the damage induced by Cs ion implantation in zirconia

International audienceSingle crystals of cubic zirconia were implanted at RT and 750 °C with increasing fluences of low energy Cs2+ ions. In situ RBS/C and TEM experiments were performed to determine the amount of damage, the nature of radiation defects and the possible occurrence of Cs precipitates as a function of the Cs fluence at both temperatures. Results indicate that the damage build-up and the nature of defects depend on the implantation temperature. TEM micrographs do not reveal the formation of any secondary phase for both implantation temperatures up to 3 at.%

Thermal behaviour of cesium implanted in cubic zirconia

International audienceCesium ions were implanted at the energy of 300 keV in YSZ at 300 and 1025 K, with increasing fluences up to 5 x 10(16) cm(-2). Concentration profiles were determined by Rutherford Backscattering Spectrometry (RBS) measurements. Transmission Electron Microscopy (TEM) experiments were achieved to determine the nature of the damages and to characterize a predicted ternary phase of cesium zirconate. At 300 K, amorphization occurs at high Cs-concentration (9 at.%) due to a chemical effect. TEM investigations performed after in situ post-annealing shows the recrystallization of YSZ concurrently with the cesium release. No precipitation of secondary phases was observed after annealing. With implantation performed at 1025 K, dislocation loops and bubbles were formed but the structure did not undergo amorphization. Dislocation rearrangement leads to the polygonization of the matrix. The cesium concentration reaches a saturation value of 1.5 at.%, and once more no precipitation is observed. (c) 2008 Elsevier B.V. All rights reserved

Cesium pre-implantation of embedded biological sections

International audienceAn ion implantation system which allows the implantation of a large surface of a specimen has been used to obtain an homogeneous enrichment with cesium of embedded biological tissues sections. In such a specimen, containing already oxygen at a high concentration, the addition of cesium allows both positive and negative secondary ions to be studied with the highest sensitivity, using the same primary ion source. (c) 2008 Elsevier B.V. All rights reserved