Institute of High Pressure Physics

In collaboration with the National Institute of Advanced Industrial Science and Technology (AIST), Japan, Prof. Shiv J. Singh’s research team has successfully investigated the influence of the cubic anvil high-pressure (CA-HP) technique on the superconducting properties of iron-based superconductors.

In this study, SmFeAsO_0.8F_0.2 (Sm1111) bulk superconductors were synthesized using the CA-HP method, and the effects of growth pressure on their superconducting properties were systematically examined. The findings revealed that ex-situ CA-HP synthesis under optimized conditions at 0.5 GPa significantly enhanced the critical current density (J_c) by an order of magnitude without altering the critical temperature (T_c). In contrast, in-situ synthesis at higher pressure and temperature conditions (4 GPa, 1400 °C, 1 h) led to a 3 K increase in T_c while maintaining strong J_c performance compared to the parent Sm1111 sample. These results demonstrate the effectiveness of the CA-HP technique as a powerful approach for optimizing and tailoring superconducting properties in iron-based superconductors.

For more details, please refer to the publication: Mohammad Azam, Tatiana Zajarniuk, Hiraku Ogino, and Shiv J. Singh entitled “Optimization of superconducting properties of F-doped SmFeAsO by cubic anvil high-pressure technique” Materials Research Express 12, 116001 (2025) (IOP Publishing). https://doi.org/10.1088/2053-1591/ae1719

Figure: Schematic illustration of (a) a typical heating temperature-time profile for the growth of SmFeAsO_0.80F_0.20 (b) the high-pressure cubic anvil apparatus, and (c) the sample cell assembly, consisting of a pyrophyllite cube, graphite sleeve, boron nitride (BN) sample crucible, pyrophyllite pellets, and graphite disks.