Ultra-high vacuum compatible induction-heated rod casting furnace

Area of Science:

• Materials Science
• Solid State Physics
• Chemical Engineering

Background:

• Processing intermetallic compounds for advanced applications requires high-purity materials.
• Existing methods often struggle with high vapor pressure elements and achieving ultra-high vacuum conditions.
• The demand for high-quality single crystals for research, such as in spintronics and thermoelectricity, is growing.

Purpose of the Study:

• To design and implement a novel radio-frequency induction-heated rod casting furnace.
• To enable the preparation of polycrystalline intermetallic compound rods under ultra-high vacuum (UHV) conditions.
• To demonstrate the furnace's capability for producing high-quality single crystals suitable for float-zoning.

Main Methods:

• A bespoke water-cooled Hukin crucible system was developed to support casting molds.
• The furnace setup is all-metal sealed, allowing for bake-out to achieve UHV.
• Processing was conducted under a high-purity argon atmosphere up to 3 bars.

Main Results:

• The developed furnace successfully produced polycrystalline rods (6-10 mm diameter, up to 90 mm length) of intermetallic compounds.
• The UHV capability proved essential for processing materials with high vapor pressures.
• Large, high-quality single crystals of the half-Heusler compounds CuMnSb (antiferromagnet) and NiMnSb (ferromagnet) were successfully prepared.

Conclusions:

• The radio-frequency induction-heated rod casting furnace is an effective tool for preparing high-purity intermetallic compounds.
• The UHV environment is critical for the successful synthesis of materials with high vapor pressures.
• This technology facilitates the production of high-quality single crystals for advanced materials research.