Strongly enhanced critical current density in Fe-sheathed MgB2 tapes by stearic acid and stearate doping

TL;DR

This study demonstrates that doping Fe-sheathed MgB2 tapes with stearic acid, Mg stearate, and Zn stearate significantly enhances their critical current density and magnetic properties, making them comparable to more expensive doping methods.

Contribution

It introduces a cost-effective doping approach using stearic acid and stearates to substantially improve MgB2 tape performance in high magnetic fields.

Findings

Jc increased by over an order of magnitude in high fields

Transport Jc reached 2.02x10^4 A/cm^2 at 10 T for Zn stearate doping

Enhanced Hc2 due to C incorporation and flux-pinning centers

Abstract

Fe-sheathed MgB2 tapes with cheap stearic acid, Mg stearate and Zn stearate doping were prepared through the in situ powder-in-tube method. It is found that Jc, Hirr, and Hc2 were significantly enhanced by doping. Compared to the pure tapes, Jc for all the doped samples was improved by more than an order of magnitude in a high-field regime. At 4.2 K, the transport Jc reached 2.02x10^4 A/cm^2 at 10 T for the Zn stearate doped tapes and 3.72x10^3 A/cm^2 at 14 T for the stearic acid doped samples, respectively, equivalent to that of tapes achieved by nanoscale SiC or carbon doping. The improvement of Jc-H properties in doped samples can be attributed to the increase of Hc2 resulting from the incorporation of C atoms into the MgB2 crystal lattice as well as a high density of flux-pinning centers.