Instytut Wysokich Ciśnień

Generally, the presence of impurity phases in a superconductor reduces its properties. Dr. Singh's research group (NL-6) has just published a new study in the Journal of Physics and Chemistry of Solids (Impact factor: 4.0) that shows the impact of impurities on high-T_c iron-based superconductors grown under ambient and applied pressure conditions.

The conclusion of this research is that the high-pressure synthesis of the stoichiometric CaKFe₄As₄ (1144) superconductor increases the transition temperature (T_c) by 2K and the critical current density (J_c) by one order of magnitude in the whole magnetic field range of 9 T as compared to that of the 1144 bulks prepared by conventional synthesis method at ambient pressure (CSP). Moreover, the superconducting onset transition temperature of this stoichiometric CaKFe₄As₄ (1144) family is robust with the presence of the common 122 (CaFe₂As₂ or KFe₂As₂) impurity phases. This study is published by “Manasa Manasa, Mohammad Azam, Tatiana Zajarniuk, Ryszard Diduszko, Tomasz Cetner, Andrzej Morawski, Andrzej Wiśniewski, Shiv J. Singh” entitled “Effect of impurity phase and high-pressure synthesis on the superconducting properties of CaKFe₄As₄”  DOI: https://doi.org/10.1016/j.jpcs.2024.111996

Figure: The variation of (a) an amount of the impurity CaFe₂As₂ phase, (b) the onset transition temperature T_c^onset, (c) the room temperature resistivity (ρ_300K), (d) Residual resistivity ratio (RRR = ρ_{300 K}/ρ_{40 K}), (e) transition width (ΔT) and (f) the critical current density (J_c) at 5 K and self-field with respect to CaKFe₄As₄ bulks prepared by high pressure and high temperature synthesis (HP-HTS) method with  1144 sample prepared by CSP method.

VIII^th Winter Workshop Kalatówki 2024 on Physics and Applications of Nitride Semiconductors will be organized on April 7-12, 2024 in Zakopane (Poland).

The Winter Workshop Kalatówki gathers researchers from the Institute of High Pressure Physics Polish Academy of Sciences and from the collaborating scientific institutes. It serves as a platform for the exchange of information and ideas among the laboratories of the Institute over the years.

Scientific topics discussed encompass the physics and technology of AlInGaN semiconductor quantum structures, particularly within the realm of light emitters. Epitaxy, device processing and theoretical modelling will be highlighted for better understanding of the underlying physics and paving the way to novel concepts realization both in optoelectronics and nitride-based electronics.

This year, we will host many prominent nitride experts:

• Prof. Tomasz Czyszanowski (Lodz University of Technology),
• Prof. Marta Gładysiewicz-Kudrawiec (Wroclaw University of Technology),
• Prof. Åsa Haglund (Chalmers University of Technology),
• Dr. Irmantas Kašalynas (Vilnius University),
• Prof. Uli Schwarz (TU Chemnitz),
• Prof. Anna Szerling (Institute of Microelectronics and Photonics, Łukasiewicz Reseach Network),
• Prof. Zbig Wasilewski (University of Waterloo)

International Conference on Nitride Semiconductors - ICNS-15 will be held in Malmö in Sweden from July 6-11, 2025.

ICNS-15 will present high-impact scientific and technological advances in materials and devices based on group-III nitride semiconductors, and feature plenary sessions, parallel topical sessions, poster sessions and an industrial exhibition. The conference is chaired by Vanya Darakchieva, Lars Samuelson and Piotr Perlin.

ICNS-15 will celebrate the achievements of Profs. Bo Monemar and Tadek Suski as honorary chairs. Save the date for this exciting event!