The alleviation of radiation-damage on Nb/MgO film driven by strain gradient in He ion irradiation

Abstract Interfaces are good traps for implanted He and radiation induced damage, and understanding the role of interfaces is important for designing highly radiation-resistant materials. In this article, Nb sheet and Nb film on MgO substrate (Nb/MgO) are irradiated by He ions, and it is found that the He bubble distribution along radiation depth between Nb sheet and Nb/MgO film is different. The comparison reveals that this difference is resulted from the diffusion of He atoms driven by strain gradient in Nb film close to Nb/MgO interface. This study could provide novel mechanisms for further understanding the interface enhancing radiation tolerance.