ANNEALING EFFECTS ON STRUCTURAL AND SUPERCONDUCTING PROPERTIES OF MgB2/Fe WIRES

Abstract

We report the results of annealing effects on structural and superconducting properties (Tc and Jc) of various MgB 2/ Fe wires that are produced by different conditions. Good quality superconducting MgB 2/ Fe wires are fabricated by the powder-in-tube (PIT) technique at ambient pressure. XRD data confirms that they are hexagonal MgB 2 structure. All the annealed samples show higher Tc values in the range of 34.6–38.4 K with Jc higher than the as-rolled wire. The annealed samples show significant change in the Jc values as well as in micro-structural features due to variable sintering temperature. On annealing at 1050°C for 10 min, we obtain the best quality sample with a Jc of 37.2 kA/cm 2 at 33.1 K and self-field with a maximum Tc of 38.4 K. Among the samples annealed at 1050°C for 5–20 min, the 20 min sample shows lower Jc. Longer annealing time (at 1050°C) reduced Jc, indicating a possible interfacial reaction between the Fe sheath and the MgB 2 core.