Direct pyrolysis method for superconducting crystalline MgB2 nanowires

Abstract

A direct pyrolysis route from MgB2 nanoparticles (100-500 nm) to crystalline MgB2 nanowires (10-20 nm diam) was developed. In this process, MgB2 nanoparticle precursor was prepared through an in situ solid reaction of Mg metal and amorphous boron powder. After directly pyrolyzing the precursor via infrared irradiation at 900 °C in a high-purity argon atmosphere, uniform MgB2 nanowires were produced at the edges of the precursor nanoparticles. Structural characterization and elemental composition analysis identified that the nanowires were made of MgB2, presumably incorporated or alloyed with some oxygen. Superconductivity of the samples was confirmed and it is indicated that the nanowires may have a transition temperature (Tc) comparable with that of bulk MgB2.