Ion irradiation induced strain and structural changes in LiTaO₃perovskite

Area of Science:

• Materials Science
• Solid State Physics
• Nuclear Materials

Background:

• Lithium tantalate (LiTaO3) is a crucial material in various optical and electronic applications.
• Understanding its response to energetic ion irradiation is vital for predicting material stability and performance in radiation environments.

Purpose of the Study:

• To investigate the effects of 3 MeV and 1.162 GeV gold (Au) ion irradiation on the crystal structure and lattice strain of LiTaO3.
• To elucidate the mechanisms of structural modification and strain relaxation induced by different irradiation energies.

Main Methods:

• Single crystal X-ray diffraction (XRD) was employed to measure lattice parameters and strain.
• Raman spectroscopy was used to probe vibrational properties and detect structural changes.
• Samples were irradiated with Au ions at specific energies and fluences.

Main Results:

• 3 MeV Au ion irradiation induced maximum lattice strains of 1.2% along the c-axis and 0.6% along the a-/b-axes.
• 1.162 GeV Au ion irradiation caused Bragg peak splitting, indicating subtle chemical composition changes.
• Subsequent irradiation with 1.162 GeV Au ions relaxed the c-axis strain from 1.2% to 0.9% in pre-damaged samples.
• Distinct changes in Raman spectra were observed for <0001> oriented samples after 1.162 GeV Au ion irradiation.

Conclusions:

• Ion irradiation significantly alters the lattice strain and structure of LiTaO3 crystals.
• The energy of the incident ions plays a critical role in the observed phenomena, with higher energies leading to more complex structural modifications and strain relaxation.
• LiTaO3's response is attributed to both inelastic ionization and elastic nuclear collision effects.