Effects of high pressure on the physical properties of MgB2

TL;DR

This paper investigates how high-pressure synthesis improves the physical properties of MgB2, resulting in dense nanograined superconducting materials with enhanced electrical, thermal, and mechanical characteristics suitable for fault current limiters.

Contribution

It demonstrates that high-pressure synthesis yields MgB2 with superior superconducting, thermal, and mechanical properties, advancing its potential for practical applications.

Findings

Critical current densities up to 1.8 million A/cm2 at 20 K

Thermal conductivity of 53 W/(m·K)

Young's modulus of 213 GPa

Abstract

The synthesis of MgB2-based materials under high pressure gave the possibility to suppress the evaporation of magnesium and to obtain near theoretically dense nanograined structures with high superconducting, thermal conducting, and mechanical characteristics: critical current densities of 1.8-1.0 \cdot 106 A/cm2 in the self field and 103 A/cm2 in a magnetic field of 8 T at 20 K, 5-3 \cdot 105 A/cm2 in self field at 30 K, the corresponding critical fields being HC2 = 15 T at 22 K and irreversible fields Hirr =13 T at 20 K, and Hirr =3.5 T at 30 K, thermal conduction of 53+/-2 W/(m \cdot \kappa), the Vickers hardness Hv=10.12+/-0.2 GPa under a load of 148.8 N and the fracture toughness K1C = 7.6+/-2.0 MPa m0.5 under the same load, the Young modulus E=213 GPa. Estimation of quenching current and AC losses allowed the conclusion that highpressure-prepared materials are promising for application in transformer-type fault current limiters working at 20-30 K.