CEC-ICMC 2015 - Timetable, Abstracts and Presentations

Significant Enhancement of Bc2 at 20-25 K for MgB2 Thin Films via Controlled oxygen doping

Jul 1, 2015, 11:45 AM

15m

Tucson Ballroom AB

Contributed Oral Presentation ICMC-05 - Thin Films M3OrA - Superconductor Wires III: Thin Films

Speaker

Guangze Li (The Ohio State University)

Description

Various dopants have been investigated for increasing Bc2 in MgB2. Most of these have not been beneficial, with the exception of C or C-bearing materials (increasing 4 K Bc2) and Dy2O3 (at higher temperatures). While Bc2 approximately doubled with C additions at 4.2 K, the high Bc2 results of the thin films have not been replicated in wires. Hence we re-investigate oxygen additions, with a focus on controlled oxygen addition for Bc2 increase. By diffusing O into PLD-made MgB2 thin films, we have successfully prepared a series of O-doped MgB2 thin films with different O concentrations. XRD shows a peak shift with the increase of O doping levels. The oxygen doping is controllable, generating a reproducible peak shift which is correlated with a significant increase in Bc2. The temperature at which Bc2 = 14 T is pushed up from 14 K to 21 K. Indeed, Bc2 is increased over the whole temperature range from 15 K to 30 K, and presumably is increased at lower temperatures as well. We also describe our efforts to realize oxygen doping in wires and the results of these measurements.