Evaluation of Mg size dependence on superconductivity of MgB₂

Abstract

MgB 2 bulk samples are synthesized through solid state reaction route using Mg precursors with different particle size by keeping the boron precursor unchanged. Scanning electron microscopy study of the fractured surface for all the samples depicts quite distinct structure depending on the Mg precursor. Big size of Mg precursor resulted in to largely elongated and deep pores while smaller one gave roughly ellipsoidal and shallow pore structure. Influence of the Mg particle size on the grain to grain connectivity reflected in the critical current density value which was greater for samples with smaller Mg precursor. All the synthesized samples undergo a superconducting transition at around 36.5 K irrespective of different Mg precursor particle size.

Low temperature decomposition of metal borohydride drives autogenous synthesis of MgB2

“…In general, microstructural studies reveal that wires formed in situ show an inherent porosity in the final MgB 2 wire due to a reduction in volume from the initial denselypacked starting materials [23]. This porosity is dependent on the particle size of starting materials [20,[24][25][26] and can be managed by temperature [27] or pressure [28][29][30] regimes and drawing methods. Nevertheless, porosity in these wires can be as high as 50% [31].…”