The effect of Fe-magnetization on I-c(B) and I-c(alpha) characteristics of iron-sheathed MgB2 composite wires

摘要

Single- and four-core MgB2 composites have been made by the powder-in-tube (PIT) method using commercial MgB2 powder in an Fe sheath. Transport currents of as-deformed wires were measured at 4.2 K and external magnetic fields B = 0-4 T. Different I-c(B) curves were observed for single- and four-core wires depending on the value of the self-field current. The behaviour I-c(B) and I-c(alpha) is influenced by Fe sheath magnetization by self-field and external field. Field distribution and I-c(B) curves were calculated using the finite element method (FEM) and they are used for an explanation of the experimental characteristics. [References: 13]