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In this study, iron-polyethylene nanocomposites were synthesized, by ion implantation with different fluences, in the range from 5 × 1016 ions/cm2 to 5×1017 ions/cm2 , and at the energy of 95 keV. Rutherford backscattering spectroscopy confirmed the presence of iron in the implanted samples, and the calculated fluences matched with those predicted, except for the highest implantation fluence, where a significant difference was due to the sputtering effect. It was also found that the depth of damage was slightly lower than predicted by the SRIM simulation [1]. X-ray photoelectron spectroscopy has revealed that implanted iron is in the form of pure metallic iron - Fe (0), and multiple iron oxides. On the other hand, carbon was mostly transformed from a sp3 hybridized, to a sp2 hybridized, indicating that the carbonization of polyethylene and the degassing of hydrogen took place. Infrared spectroscopy has indicated that aldehydes and ketones are formed after implantation, and that many organic compounds are likely to form upon implantation with the highest fluence. Atomic force microscopy confirmed that implantation led to considerable destruction of the surface, resulting in changes of surface morphology, and a considerable increase of surface roughness [2]. Transmission electron microscopy microphotographs show that after implantation, iron nanoparticles are formed, and the particle sizes have a characteristic depth distribution, according to which they can be classified into three zones. However, a continuous layer is formed in the case of the highest implantation fluence. Energy dispersive spectrophotometric analysis of a single particle indicated that the nanoparticle interior was mainly composed of pure metallic iron, and that the iron oxides probably dominated near the very surface of the nanoparticles [1]. From the measurements of the sheet resistivity by the 4-point contact probe method, it was observed that between the 1×1017 ions/cm2 and 2×1017 ions/cm2 fluences, a transition occurs in which the metal phase takes a dominant role in the mechanism of electric conduction and that percolation most likely is achieved for fluences in the range between 2×1017 ions/cm2 and 5 × 1017 ions/cm2 [2]. Measurements by Kerr magneto-optical magnetometry have indicated that the magnetic properties change in accordance with the applied implantation fluence and the morphology of the iron nanoparticles formed in the surface layer. The occurrence of the ferromagnetic phase can be observed for the two higher fluences, with a coercivity of only 20 Oe for the fluence of 2×1017 ions/cm2 , whereas for the highest fluence of 5×1017 ions/cm2 , the coercivity is 57 Oe. The shape of hysteresis loop is typical of a mixture of single and multi-domain particles. UV-VIS spectroscopy showed that, as a consequence of implantation, the peaks in the Kubelka - Munk spectra of remission function appear [1], most likely originating from localized surface plasmon resonance of the iron nanoparticles [3,4]. Surface energy changes with the implantation fluence, in a way that it increases up to a fluence of 1 × 1017 ions/cm2 , and then decreases with increasing fluence. It was also found that the hydrophobic, i.e. dispersive character of the surface does not change significantly as a consequence of implantation [2]. VIII International School and Conference on Photonics and HEMMAGINERO workshop : PHOTONICA2021 : book of abstracts; August 23-27, 2021; Belgrade |
