ABSTRACT
We present the results of the irreversibility field (Birr), critical temperature (Tc), and magnetic critical current density (Jcm) for cylindrical samples encapsulated in carbon and doped with 1-3 at% dysprosium and terbium oxides. All samples were analyzed microstructurally by using a scanning electron microscope (SEM) and X-ray diffraction (XRD). The influence of annealing temperature and time and high isostatic pressure on Jcm was investigated. Our results show that double-doped (C + Tb2O3 and C + Dy2O3) and low isostatic pressure heat treatment (0.1 MPa) decrease the Tc by about 0.5 K compared to the undoped MgB2 (0.1 MPa). The magnetic measurements show that double-doped and heat treatment under high isostatic pressure (HIP - 1 GPa) leads to a decrease in Tc of about 2.5 K compared to the undoped MgB2 sample after the HIP process. Our results show that the HIP process slightly increases Jcm at 4.2 K and 20 K, and improves Jcm at 30 K in undoped MgB2 samples. Furthermore, our results show that the HIP process and double-doped significantly increase Jcm at 4.2K and decrease Jcm at 30K. Our results indicate that the HIP process can produce high field and low-temperature pinning centers in doubly doped MgB2 materials.
Disclosure statement
No potential conflict of interest was reported by the author(s).