  The high-pressure growth technique generally plays an important role in the
improvement of the sample quality and the enhancement of various physical and
magnetic properties of materials. The high gas pressure technique provides a
large sample space (10-15 cm) to grow various kinds of materials. In this
paper, we introduce the high gas pressure and high-temperature synthesis
(HP-HTS) technique that is present at our institute and is applied to the
growth process of different kinds of superconducting materials, particularly
iron-based superconductors. More details and the working principle of this
HP-HTS technique are discussed. We have also demonstrated the current results
based on the iron-based superconductors by using this unique HP-HTS technique.
These results demonstrate the enhancement of the superconducting properties
with the improved sample quality compared to the conventional synthesis process
at ambient pressure.
