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Optical floating-zone furnaces
Four optical floating-zone furnaces (Greven and Xianghan) allow for crucible-free growth of large, high-quality crystals under extreme thermodynamic conditions. These furnaces use focused light/high-pressure laser to melt a precursor feed rod and grow a crystal from a seed crystal with a steep thermal gradient and precise control of the molten zone. The furnaces are capable of temperatures up to 3000 °C under a variety of controlled atmospheres, including high oxygen partial pressures, enabling access to metastable and highly oxidized materials not achievable by conventional growth methods.
Box furnaces
Standard box furnaces are used for the bulk fabrication, including the growth of the Hg-based cuprates using the encapsulated self-flux growth method. The Center has 12 standard box furnaces with maximum temperatures of 1100 - 1200 °C, and a high-temperature muffle furnace capable of up to 1600 °C. Many of the furnaces can run a customized temperature vs time program. Sealing the growth materials in a welded quartz tube allows for high vapor pressures during crystal growth.
Tube furnaces
Tube furnaces are used for crystal growth by chemical vapor deposition, post-growth annealing, and heat treatment. These include eight one-zone furnaces capable of up to 1100 °C, and two three-zone furnaces with maximum temperatures of 1200 °C and 1350 °C. Most of these furnaces are equipped with manifolds for gas flow and/or high-vacuum pumping.
Chemical vapor transport furnaces
The Leighton Lab houses two vapor-transport setups based on three-zone furnaces with high capacity. Each system is set up to enable six parallel growths in quartz tubes, greatly increasing sample throughput. These systems are used for growth of doped pyrite NiS2, and delafossite PdCoO2 and PdCrO2, for example.
Arc Melting and Vacuum Casting System
The system is used for the synthesis of high-purity metallic and intermetallic compounds under controlled inert atmospheres. It is equipped with a customized vacuum casting module that enables direct casting of molten metals into dense, uniform rods, which can be used for subsequent single-crystal growth using the floating-zone technique, ensuring excellent compositional homogeneity and mechanical integrity for crystal growth applications.
Material handling equipment
The Center has three glove boxes and numerous fume hoods for safely handling hazardous materials and maintaining the purity of chemicals and samples during crystal growth preparation and sample preparation.
Folwell Component
A tube furnace and several box furnaces used for bulk fabrication
Arc melting and vacuum casting system
Three-zone tube furnaces for chemical vapor transport
Funded by the Department of Energy under DE-SC0016371
