A 3D Printed Superconducting Aluminium Microwave Cavity

TL;DR

This paper demonstrates that a 3D printed aluminium alloy with high silicon content can exhibit superconductivity at low temperatures, enabling new possibilities for manufacturing superconducting microwave cavities.

Contribution

It reveals that 3D printed Al-12Si alloy can become superconducting below 1.2 K, despite high silicon content, expanding the potential for 3D printed superconducting devices.

Findings

Superconductivity observed at 9.9 and 11.2 GHz frequencies.

Superconducting performance comparable to standard aluminium alloys.

Superconductivity achieved with 12.18% silicon content.

Abstract

3D printing of plastics, ceramics, and metals has existed for several decades and has revolutionized many areas of manufacturing and science. Printing of metals in particular has found a number of applications in fields as diverse as customized medical implants, jet engine bearings, and rapid prototyping in the automotive industry. Whilst many techniques can be used for 3D printing metals, they commonly rely on computer controlled melting or sintering of a metal alloy powder using a laser or electron beam. The mechanical properties of parts produced in such a way have been well studied, but little attention has been paid to their electrical properties. Here we show that a microwave cavity (resonant frequencies 9.9 and 11.2 GHz) 3D printed using an Al-12Si alloy exhibits superconductivity when cooled below the critical temperature of aluminium (1.2 K), with a performance comparable to the common 6061 alloy of aluminium. Superconducting cavities find application in numerous areas of physics, from particle accelerators to cavity quantum electrodynamics experiments. The result is achieved even with a very large concentration of non-superconducting silicon in the alloy of 12.18%, compared to Al-6061, which has between 0.4 to 0.8%. Our results may pave the way for the possibility of 3D printing superconducting cavity configurations that are otherwise impossible to machine.