AMORPHIZATION IN GD2TI2O7 AND CAZRTI2O7 IRRADIATED WITH 3 MEV ARGON IONS

Irradiation of Gd2Ti2O7 and CaZrTi2O7 with 3 MeV Ar+ ions results in the simultaneous expansion of the unit-cell volume and radiation-induced amorphization. The damage cross sections for amorphization, which were determined by X-ray diffraction, are 0.023 nm2 and 0.014 nm2, respectively. These damage cross sections are relatively low and suggest some inherent resistance of these structures to amorphization, in agreement with previous studies. Transmission electron microscopy and electron diffraction confirmed the amorphous character of both materials at high fluences. Raman spectroscopy indicated a decrease in scattered intensity with ion fluence for the Raman-active vibrational modes of Gd2Ti2O7 and CaZrTi2O7. In the case of Gd2Ti2O7, increases in both linewidth and wavenumber with ion fluence also were observed.