Influence of carbon-ion irradiation on the superconducting critical properties of MgB\(_2\) thin films

• Published in: arXiv.org
• Main Authors: Soon-Gil, Jung, Seung-Ku Son, Pham, Duong, Lim, Weon Cheol, Song, Jonghan, Won Nam Kang, Park, Tuson
• Format: Paper
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 14.11.2018
• Subjects: Atomic properties; Borides; Carbon; Critical field (superconductivity); Fluence; Ion irradiation; Parameters; Phase transitions; Properties (attributes); Residual resistivity; Superconductivity; Temperature; Thickness; Thin films; Transition temperature
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1811.05814

We investigate the influence of carbon-ion irradiation on the superconducting critical properties of MgB\(_2\) thin films. MgB\(_2\) films of two thicknesses viz. 400 nm (MB400nm) and 800 nm (MB800nm) were irradiated by 350 keV C ions having a wide range of fluence, 1 x 10\(^{13}\) - 1 x 10\(^{15}\) C atoms/cm\(^2\). The mean projected range (\(R_p\)) of 350 keV C ions in MgB\(_2\) is 560 nm, thus the energetic C ions will pass through the MB400nm, whereas the ions will remain into the MB800nm. The superconducting transition temperature (\(T_c\)), upper critical field (\(H_{c2}\)), \(c\)-axis lattice parameter, and corrected residual resistivity (\(\rho_{corr}\)) of both the films showed similar trends with the variation of fluence. However, a disparate behavior in the superconducting phase transition was observed in the MB800nm when the fluence was larger than 1 x 10\(^{14}\) C atoms/cm\(^2\) because of the different Tcs between the irradiated and non-irradiated parts of the film. Interestingly, the superconducting critical properties, such as \(T_c\), \(H_{c2}\), and \(J_c\), of the irradiated MgB\(_2\) films, as well as the lattice parameter, were almost restored to those in the pristine state after a thermal annealing procedure. These results demonstrate that the atomic lattice distortion induced by C-ion irradiation is the main reason for the change in the superconducting properties of MgB\(_2\) films.