Investigation of the Effect of Low Purity Boron on the Critical Properties of L-IMD MgB2 Wires

Abstract

MgB₂/Fe superconducting wires were synthesized by sintering at 850 °C for 2 h using low purity B source by using the Localized Internal Mg Diffusion (LIMD) technique, a type of powder-in-tube method. The formation of locally dense MgB₂ regions was targeted with the LIMD technique. In the phase examination of the products by X-ray diffraction, the main phase was determined to be MgB₂. Lattice parameters and MgO fraction were determined by the Rietveld refinement process. Microscope and scanning electron microscope images revealed that the core parts contained thin and long structures. Magnetic measurements showed that they exhibited a sharp transition interval, and the magnetic critical current density calculated with the Bean Model was in the order of 10⁵ A/cm². Pinning force analysis showed that the surface pinning mechanism of the samples was the dominant mechanism. Electrical transport measurements were made using short core samples, and the best resistivity value was obtained in the sample using 86 wt% B source. The transport critical current density values obtained from transport measurements made with long samples at 4.2 K were found to be comparable with the literature. Among the purity levels of 86 wt% and 95 wt% examined in this study, the results of the sample using 86% purity boron were found to be partially improved.