Surface layer morphology of the high fluence Fe implanted polyethylene - Correlation with the magnetic and optical behavior

Fe/Polyethylene nanocomposite was synthesized by ion beam implantation of 56Fe+ into bulk high-density polyethylene. Nanoscale surface morphology along with magnetic and optical behavior was investigated. The aim of the research was to investigate changes of polyethylene's surface layer morphology with the change of Fe implantation fluence in the high fluence range and to find correlations with the magnetic and optical behavior. Four implantation fluences were applied: 5 × 1016, 1 × 1017, 2 × 1017 and 5 × 1017 cm−2, while the implantation energy was 95 keV. Concentration profiles of implanted Fe were analyzed by Rutherford backscattering spectrometry, showing Fe concentration profile maxima closer to the surface with increasing implantation fluence. Cross-sectional transmission electron microscopy showed the formation of metallic nanoparticles with sizes in a range from below 1 nm up to few tens of nanometers, depending on the fluence, and for the highest implantation fluence, a continuous layer was formed. Magneto-optic Kerr effect magnetometry demonstrates weak ferromagnetic behavior for the 2 higher fluences, and superparamagnetic for the 2 lower fluences. The UV-VIS remission function spectra show the peak in the UV region, which we attribute to iron nanoparticles.