Effect of O+ ion irradiation on the magnetic properties of superconducting magnesium diboride composites

The results of a study on the effect of ion irradiation (O+ ions, E = 20 keV) in radiation defect generation modes on the critical temperature and current of high-temperature superconducting magnesium diboride (MgB₂) composites are presented. An analysis was performed, including both the integral critical current derived from sample magnetization measurements and the determination of the critical temperature from vibrating sample magnetometry data. It is shown that at an ion fluence of 1·10¹³ ions/cm², a 3.5-fold increase in the critical current density (Jc) is observed in the radiation defect generation regime. In contrast, at a fluence of 1·10¹⁴ ions/cm², a slight decrease in Jc is observed, along with the absence of a Meissner phase in the superconductor bulk, as indicated by vibrating sample magnetometry.