Investigations of nano-defect morphology and vibrational spectra of swift heavy ion irradiated muscovite mica

Abstract Muscovite mica sheets with a thickness of 12 μm were irradiated by various kinds of swift heavy ions in Heavy Ion Research Facility in Lanzhou (HIRFL). During the irradiation process, the fluence was kept in the range 1 × 10 10 –1 × 10 12  ions/cm 2 , whereas the electronic stopping power S e was in the range from 5.9 to 31.5 keV/nm. The vibrational modifications in irradiated mica were investigated by Fourier-transform infrared (FTIR) spectroscopy and the morphology of the nano-defects on the surface of mica was analyzed by the atomic force microscopy (AFM) in the tapping mode. The infrared spectrum showed that motions from all atomic types in the muscovite mica structure could be found in modes for all vibrations. The intensity of all observed vibrational modes, including the O H stretching motion at 3621 cm −1 , was found to decrease with increasing S e values and ion fluences. It was indicated that formation of the defects and structural modifications take place in muscovite mica as a result of swift heavy ion irradiation, and it was found that more defects were introduced in mica by irradiation with higher ion fluences and higher electronic stopping power S e values. The morphology of nano-defects on the surface of mica that depends on the applied S e was discussed in detail this work. Craters were observed in the samples irradiated by Xe ions with electronic stopping power of 21.8 keV/nm or by Bi ions with electronic stopping power of 31.5 keV/nm. While the hillocks with craters on the top were found on the surface of mica irradiated by Kr ions with S e values of 9.0 keV/nm.