Superconductivity, critical current density, and flux pinning in MgB_{2-x}(SiC)_{x/2} superconductor after SiC nanoparticle doping

TL;DR

This study explores how SiC nanoparticle doping affects the structure, critical temperature, and flux pinning in MgB_2 superconductors, revealing improved critical current density due to defect creation and nano-inclusions.

Contribution

It introduces a detailed analysis of SiC doping effects on MgB_2, highlighting defect-induced flux pinning and proposing a new pinning mechanism.

Findings

SiC doping causes lattice contraction and slight T_c depression.

High doping levels create effective vortex pinning centers.

Enhanced J_c performance due to intra-grain defects and nano-inclusions.

Abstract

We investigated the effect of SiC nano-particle doping on the crystal lattice structure, critical temperature T_c, critical current density J_c, and flux pinning in MgB_2 superconductor. A series of MgB_{2-x}(SiC)_{x/2} samples with x = 0 to 1.0 were fabricated using in-situ reaction process. The contraction of the lattice and depression of T_c with increasing SiC doping level remained rather small due to the counter-balanced effect of Si and C co-doping. The high level Si and C co-doping allowed the creation of intra-grain defects and highly dispersed nano-inclusions within the grains which can act as effective pinning centers for vortices, improving J_c behavior as a function of the applied magnetic field. The enhanced pinning is mainly attributable to the substitution-induced defects and a local structure fluctuations within grains. A pinning mechanism is proposed to account for different contributions of different defects in MgB_{2-x}(SiC)_{x/2} superconductors.