Institute of High Pressure Physics

FeSe is the simplest iron-based superconductor and has a layered structure with alternating Fe and Se layers. Dr. Singh's research group from our Institute has studied the chemical pressure effect by substitution of the Pr element at Fe sites and As-substitution at Se-sites in FeSe compound. Conventional synthesis process (CSP) at ambient pressure and high-pressure growth technique were used. Interestingly, Pr doping at Fe sites preserves T_c^onset and improves J_c of FeSe_0.5Te_0.5 regardless of the doping contents and growth conditions. More detail about this study can be found in the recently published paper by: Priya Singh, Manasa Manasa, Mohammad Azam, Tatiana Zajarniuk, Svitlana Stelmakh, Taras Palasyuk, Jan Mizeracki, Tomasz Cetner, Andrzej Morawski, Cezariusz Jastrzębski, Michał Wierzbicki, Shiv J. Singh entitled “Praseodymium doping effect on the superconducting properties of FeSe_0.5Te_0.5 bulks under ambient and high-pressure growth conditions” Physica C: Superconductivity and its Applications (Elsevier) 633, 1354729 (2025); https://doi.org/10.1016/j.physc.2025.1354729

Figure: The variation of (a) the onset transition temperature (T_c) (b) the transition width (ΔT) (c) the room temperature resistivity (ρ_300K) (d) residual resistivity ratio (RRR = ρ_300K / ρ_20K) (e) the critical current density (J_c) at 7 K for H = 0 T (closed symbol) and 3 T (open symbol) for Pr_xFe_1-xSe_0.5Te_0.5 bulks prepared by high pressure growth method with respect to the nominal contents (x) of Pr substitutions or Gd- additions.

In the second research paper, Dr. Singh’s research group has concluded their findings on the effects of As-substitution at Se sites in the FeSe system. The observed superconducting transition temperature is approximately 12 K, which is higher than that of the parent compound FeSe_1-x. This paper is published by: Priya Singh, Manasa Manasa, Mohammad Azam, Tatiana Zajarniuk, Konrad Kwatek, Tomasz Cetner, Andrzej Morawski, Jan Mizeracki and Shiv J. Singh entitled “Synthesis and characterizations of arsenic doped FeSe bulks” Journal of Superconductivity and Novel Magnetism 38, 109 (2025) https://doi.org/10.1007/s10948-025-06952-5