Technology Commercialization and Partnerships | BSA 04-29: Improved Growth of High-Temperature Superconductors with HF Pressure Control

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Categories: advanced materials, energy

BSA 04-29: Improved Growth of High-Temperature Superconductors with HF Pressure Control

BNL Reference Number: BSA 04-29

Patent Status: U.S. Patent Number 7,622,426 was issued on November 24, 2009

Summary

Graphical representation of the removal of hydrogen fluoride gas by the absorber during growth of YBa₂Cu₃O₇ (YBCO)

A new method of growing high-temperature superconductors controls hydrogen fluoride gas pressure and creates larger, more uniform crystal structures in these versatile materials. Superconductors offer extreme efficiency by transmitting electric current without any dc resistive loss, and high-temperature versions further reduce cost by requiring less extreme cooling. This process of growing the crystalline structures in cuprate superconductors promises higher quality fabrication for a broad range of applications.

Description

Accumulation of hydrogen fluoride (HF) gas creates a significant obstacle in the uniform growth of high-temperature superconductors, which operate at temperatures higher than the boiling point of liquid nitrogen. HF restricts the growth area of crystalline structures and can be dangerous if uncontrolled. Precisely controlling the HF vapor pressure during growth produces crystalline superconductors with highly-oriented atomic structures. The barium ﬂuoride or “ex situ process” is being applied to the growth of YBa2Cu3O7 (YBCO) layers on flexible metallic substrates. But HF, a product of the conversion of the YBCO ﬂuorinated precursor to crystalline YBCO, can quickly accumulate in an ex situ reactor and stop the growth of YBCO. This solution to the problem of HF build-up and subsequent nonuniformity relies on the removal of HF by chemical absorption using a solid absorber. A solid HF absorber allows for the implementation of a one-dimensional solution to the hydrodynamic problem of achieving HF partial pressure uniformity.

Benefits

This method provides an efficient way to remove hydrogen fluoride gas from chemical fabrication processes and yields high quality crystalline end products. The process can be easily implemented to increase rate and quality of fabrication, and it allows for larger diameter HTS production and lower manufacturing costs. The higher uniformity also yields a more versatile product.

Applications and Industries

The process allows improved fabrication of materials essential for high-temperature superconductors, optical devices, and microelectronics used by a wide range of industries.