Enhanced interface pinning and aging by high pressure oxygenation of melt textured Nd1+xBa2−xCu3O7−δ

TLDR: In this article, it was shown that when high p O 2 treatments are properly chosen, Nd123/422 interfaces become the dominant flux pinning center, strongly increasing the critical currents at low and intermediate magnetic fields.

Abstract: A competing effect inducing both an enhancement of interface pinning and aging of the critical currents has been established in NdBa 2 Cu 3 O 7− δ /Nd 4 Ba 2 Cu 2 O 10 (Nd123/422) melt-textured ceramic composites upon high oxygen pressure annealing. We demonstrate that, when high p O 2 treatments are properly chosen, Nd123/422 interfaces become the dominant flux pinning centre, strongly increasing the critical currents at low and intermediate magnetic fields. It is suggested that Nd123/422 interfaces are enriched in antisite defects, which are properly oxygenated only upon high p O 2 annealing. Additional evidence for the enhanced oxygenation is gained from the observation of a consequent decrease of the field induced anomaly at intermediate fields. A second consequence of high pressure oxygenation is the appearance of an aging effect in the critical currents and irreversibility line. This is the first time that aging is described in Nd123/422 ceramic composites.