Ultra-high vacuum compatible induction-heated rod casting furnace

TL;DR

This paper presents a novel ultra-high vacuum compatible induction-heated furnace designed for preparing high-purity intermetallic compound ingots, enabling the growth of large, high-quality single crystals for advanced materials research.

Contribution

The design introduces a fully sealed, bakeable induction furnace with a bespoke crucible system suitable for processing high vapor pressure compounds under ultra-high vacuum conditions.

Findings

Successfully produced large single crystals of CuMnSb and NiMnSb.

Demonstrated the furnace's capability to process high vapor pressure intermetallics.

Enabled high-purity crystal growth suitable for fundamental studies.

Abstract

We report the design of a radio-frequency induction-heated rod casting furnace that permits the preparation of polycrystalline ingots of intermetallic compounds under ultra-high vacuum compatible conditions. The central part of the system is a bespoke water-cooled Hukin crucible supporting a casting mold. Depending on the choice of mold, typical rods have a diameter between 6 mm and 10 mm and a length up to 90 mm, suitable for single-crystal growth by means of float-zoning. The setup is all-metal sealed and may be baked out. We find that the resulting ultra-high vacuum represents an important precondition for processing compounds with high vapor pressures under a high-purity argon atmosphere up to 3 bar. Using the rod casting furnace, we succeeded to prepare large high-quality single crystals of two half-Heusler compounds, namely the itinerant antiferromagnet CuMnSb and the half-metallic ferromagnet NiMnSb.