Ion-induced Phase Change of Zr Film on Sapphire

Formation of High Pressure Phase

Abstract

Crystalline phase transformation from α-phase to ω-phase(high pressure phase) was found to occur in Zr thin film on sapphire when it was irradiated with N⁺ or Ar⁺ions at low temperature. Ion irradiation at ambient temperature caused only grain growth of the α-phase. The ω-phase formation is tentatively attributed to crystal growth in collision cascade under large compressive stress which was generated by preceding irradiation.