High Critical Current Density in the Textured Nanofiber Structure in Multifilament MgB 2 Wires Made by the Powder-In-Tube (PIT) Technique.

We show that the structure of multifilament MgB 2 wires made by the powder-in-tube (PIT) method can be texturized by annealing the structure under high isostatic pressure. Our results show that we obtained continuous fibers with a uniform diameter of 250 nm in all 36 filaments, a small grain size of approximately 50 nm and a high density of the superconducting material. These results contribute to a significant improvement in the critical current density in high magnetic fields, e.g., 100 A/mm 2 at 14 T and 4.2 K.