Article
Chemistry, Physical
Minoru Maeda, Akiyoshi Matsumoto, Gen Nishijima, Yoon-Uk Heo, Seungyong Hahn, Sangjin Lee, Seyong Choi, Jung Ho Kim
Summary: In this study, the researchers proposed a method of regulating porous properties using magnesium powder blending. Through a detailed investigation, they found a significant correlation between various particle parameters, impurities, superconducting transition temperature, and current carrying capacity, with the porous properties. The blending of raw powders with spherical shape allowed for tuning of morphological structures and crystallinities inside the cores of the MgB2 superconducting wires, resulting in superior superconducting properties. This finding provides valuable insights for the widespread use and application of superconducting materials.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Physics, Applied
Zilin Gao, Chris R. M. Grovenor, Susannah C. Speller
Summary: The microstructure of polycrystalline MgB2 significantly affects its current carrying ability, with grain boundaries and non-superconducting nanoparticles acting as good flux pinning centers. Previous studies have shown that hBN doping improves intrinsic critical current density (Jc) and Mg doping improves extrinsic Jc. In this study, the co-doping effect of 5 wt.% Mg and 1 wt.% hBN on bulk MgB2 samples fabricated using field assisted sintering is investigated. Furthermore, the influence of ball milling and processing temperatures on Mg-doped samples is also reported. The presence of Mg liquid during processing accelerates the reaction between BN and MgB2, forming an impurity phase, MgNB9, which adversely affects superconducting performance. However, a significant improvement in performance is achieved by increasing the sintering temperature in samples doped only with Mg.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Hasan Durmus, Kemal Kocabas
Summary: A series of nano-sized Mn polycrystalline-substituted MgB2 samples were synthesized by solid-state reaction method. It was found that Mn substitution significantly suppressed the superconducting transition temperature and altered the magnetization behavior. The self-field critical current density of the samples decreased with increasing Mn substitution ratio, and the presence of surface pinning mechanism was observed.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2022)
Article
Materials Science, Multidisciplinary
Chunsheng Gong, Shanshan Sun, Shaohua Wang, Hechang Lei
Summary: The introduction of Cu quickly suppresses superconductivity in FeSe single crystals, induces a metal-insulator transition, and has minor effects on magnetic fluctuations. Additionally, Cu doping significantly decreases electron mobility, which is detrimental to superconductivity.
Article
Materials Science, Ceramics
Zilin Gao, Sangeeta Santra, Sajjad Amirkhanlou, Edwin Eardley, Chris Wort, Chris R. M. Grovenor, Susannah C. Speller
Summary: Nanocrystalline MgB2 bulk superconductors with superior performance were fabricated using ultra-high pressure-assisted sintering. The obtained superconducting properties were attributed to the combination of limited grain growth, retained crystal defects, and complete densification achieved by ultra-high pressure. The study highlights the importance of microstructure in controlling the superconducting behavior in sintered MgB2.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2022)
Article
Multidisciplinary Sciences
Wuhao Chen, Xiaoli Huang, Dmitrii V. Semenok, Su Chen, Di Zhou, Kexin Zhang, Artem R. Oganov, Tian Cui
Summary: This study successfully synthesized hcp-(La,Ce)H9-10 at 113GPa and observed high-temperature superconductivity at 176K and 100GPa, with an extrapolated upper critical field of 235T. The superconducting properties of La-Ce-H were significantly enhanced compared to the binary La-H and Ce-H compounds, indicating the potential of solid solution for improving superconductors.
NATURE COMMUNICATIONS
(2023)
Article
Physics, Applied
Sergey L. Bud'ko, Mingyu Xu, Paul C. Canfield
Summary: This study presents measurements of temperature dependent magnetization associated with trapped magnetic flux in single crystals of CaKFe4As4, CaK(Fe0.983Mn0.017)(4)As-4, and MgB2 using zero-field-cooled and field-cooled protocols. The results provide values for the superconducting transition temperature, lower critical field, and self-field critical current density and are compared with literature data. Potential experimental concerns are briefly discussed. The results of this study, on known superconductors at ambient pressure, exhibit qualitative similarities to recent measurements on superhydrides at megabar pressures, and can serve as a baseline for interpreting high-pressure trapped flux measurements.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Suman Nandi, Souvik Sasmal, Bishal Baran Maity, Vikash Sharma, Gourav Dwari, Ruta Kulkarni, A. Thamizhavel
Summary: A single crystal of NbReSi with a hexagonal structure and noncentrosymmetric space group P6 over bar 2m (No. 189) was grown by the Czochralski method. Its anisotropic physical properties were investigated through measurement of magnetic susceptibility and electrical transport. The superconducting transition temperature (Tc) is 6.1 K and the upper critical field (Hc2) values are 8.39 T and 11.65 T for different field orientations. The presence of strong pinning in the sample is indicated by a calculated critical current of the order 104 A/cm2.
Article
Materials Science, Ceramics
I. Husek, P. Kovac, T. Melisek, M. Hain
Summary: Superconducting joints between single-core MgB2/Ni and MgB2/Nb wires were manufactured using an internal Mg diffusion (IMD) process and scarf joints architecture. The transport currents of the joints were measured and compared with the currents of the used MgB2 wires under different conditions. The structure of the joints was analyzed by an optical microscope. It was found that adding boron powder between the joined wires allows for the creation of superconducting current paths. The interaction between Mg and Ni inside the joint area affects the formation of the MgB2 phase and degrades the critical current, while joints between MgB2/Nb wires have no inter-metallic interactions and show large critical currents.
CERAMICS INTERNATIONAL
(2023)
Article
Chemistry, Physical
I. P. Studenyak, A. I. Pogodin, M. J. Filep, O. I. Symkanych, T. Y. Babuka, O. P. Kokhan, P. Kus
Summary: High-quality single crystals of Ag6+x(P1-xGex)S5I solid solutions were grown by vertical zone crystallization method. The crystal structure and ion transport mechanism were studied using XRD analysis and impedance spectroscopy, showing the peculiarities and maxima of the ionic component in the solid solutions.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Engineering, Electrical & Electronic
E. Taylan Koparan, S. B. Guner, C. Aksoy, B. Savaskan
Summary: This research study examines the crystallography, flux pinning mechanism, microstructure, and superconducting properties of MgB2 samples co-added with nano-Pt/nano-SiC. XRD analysis reveals the presence of impurity phases (Mg2Si, Pt3Si, and Mg2PtSi) in the co-added samples, which act as influential pinning centers for the flux lines. The addition of nano-SiC and nano-Pt improves the critical current density (Jc) at high magnetic fields (B > 4 T).
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Yu Lin, Yutong Liu, Liang Zheng, Dajin Zhou, Zhou Yu, Yongliang Chen, Xinsheng Yang, Cuihua Cheng, Yong Zhang, Yong Zhao
Summary: MgB2 superconducting materials show significant application potential at 20K, but currently lag behind other superconductors in terms of current-carrying capacity. Chemical doping, specifically with NaCl, has been shown to improve grain connectivity and refine grain structure in MgB2, potentially enhancing its superconducting properties. Additionally, smaller MgB2 grain sizes exhibit better matching with surface pinning characteristics according to Kramer's theory.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2021)
Article
Physics, Multidisciplinary
H. Sakai, Y. Tokiwa, P. Opletal, M. Kimata, S. Awaji, T. Sasaki, D. Aoki, S. Kambe, Y. Tokunaga, Y. Haga
Summary: The superconducting phase diagram in uranium ditelluride was investigated using high-quality single crystals under magnetic fields along the hard magnetic b axis. Low-field and high-field superconducting phases with different field-angular dependence were distinguished through electrical resistivity and ac magnetic susceptibility measurements. The crystal quality affected the upper critical field of the low-field superconducting phase, but the H* value at which the high-field superconducting phase appeared remained the same across different crystals. A phase boundary signature was also observed inside the low-field superconducting phase near H*, indicating the presence of an intermediate superconducting phase characterized by small flux pinning forces.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Zhao Liu, Biao Wang
Summary: The effect of biaxial strain on the superconducting properties of MgB2 monolayer was studied using first-principles calculations. The results showed that tensile biaxial strain increased the critical temperature of MgB2, while compressive biaxial strain decreased it. The microscopic mechanism of this strain effect was investigated through electronic structure and phonon dispersion calculations.
MATERIALS CHEMISTRY AND PHYSICS
(2022)
Article
Physics, Multidisciplinary
Jia-Ming Zhao, Zhi-He Wang
Summary: In this study, we investigated the anisotropic electrical transport and magnetic properties of FeSe0.5Te0.5 single crystals grown by the self-flux method. The in-plane resistivity exhibited a metallic-like temperature dependence, while the out-of-plane resistivity showed a broad hump at around 64 K. The magnetization loops for H//c-axis and H//ab-plane were also different, with a typical second peak observed for H//c-axis. The in-plane critical current density was higher than the out-of-plane critical current density. The coherence length and penetration depth were estimated using the Ginzburg-Landau theory. The anisotropic parameter gamma depended on the applied magnetic field and temperature. The coupling of superconducting FeSe(Te) layers and the flux pinning mechanism relevant to anisotropy were also discussed.
Article
Materials Science, Multidisciplinary
Y. Konopelnyk, I Radelytskyi, P. Iwanowski, D. J. Gawryluk, M. Berkowski, R. Diduszko, J. Fink-Finowicki, H. Szymczak, R. Puzniak
Summary: The impact of hydrostatic pressure on the magnetic entropy change in Fe7Se8 single crystals was investigated. The results show that the application of hydrostatic pressure affects the spin-reorientation transition temperature and magnetization of Fe7Se8, which in turn influences the magnetic properties. The experimental findings suggest that the magnetic entropy change and refrigeration capacity of the crystals strongly rely on the spin-reorientation transition temperature and therefore on hydrostatic pressure.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Physics, Multidisciplinary
J. Gosk, R. Puzniak, A. Lynnyk
Summary: The magnetization of monocrystalline ZnO samples implanted with magnetic Co and with Ar and Kr noble gases ions was investigated. It was found that Co-implanted ZnO samples showed paramagnetic and residual ferromagnetic/superparamagnetic phases, while the implants of Ar and Kr did not introduce magnetic centers.
ACTA PHYSICA POLONICA A
(2022)
Article
Automation & Control Systems
Paolo Tripicchio, Matteo Unetti, Salvatore D'Avella, Alice Buffi, Andrea Motroni, Fabio Bernardini, Paolo Nepa
Summary: This study proposes a reliable 2-D localization methodology that leverages a phase-distance model, synthetic aperture approach, and unwrapping techniques. By applying trilateration and analytic calculus, intersections among conics are computed to estimate tag positions accurately.
IEEE TRANSACTIONS ON AUTOMATION SCIENCE AND ENGINEERING
(2022)
Article
Chemistry, Inorganic & Nuclear
Edyta Pesko, Artem Lynnyk, Aldona Zalewska, Roman Puzniak, Anna Krzton-Maziopa, Stanislaw Kus
Summary: The electrochemical intercalation of alkali metal - pyridine adducts into iron selenide matrix was investigated. The charge transfer resistance increased with reaction time, and structural transition was observed. The introduction of guest species and the magnetic and superconducting properties of the samples were confirmed through various experimental techniques.
JOURNAL OF SOLID STATE CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Nikolai D. Zhigadlo, Roman Puzniak
Summary: The iron-based oxypnictide superconductor SmFeAsO0.8F0.2 was synthesized under high pressure and showed bulk superconductivity along with antiferromagnetic behavior. The significant jump in magnetization observed at low temperature suggests a spin-glass-like behavior in this material.
MENDELEEV COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
Jean-Baptiste Vaney, Baptiste Vignolle, Alain Demourgues, Etienne Gaudin, Etienne Durand, Christine Labrugere, Fabio Bernardini, Andres Cano, Sophie Tence
Summary: This article introduces a topochemical method for intercalating fluorine atoms into intermetallics and demonstrates its potential by synthesizing non-stoichiometric mixed anion LaFeSiFx single crystals, which exhibit FeSi-based superconductivity. The study shows that fluorine topochemistry on intermetallics is an effective route for providing functional materials.
NATURE COMMUNICATIONS
(2022)
Article
Materials Science, Multidisciplinary
F. Bernardini, A. Bosin, A. Cano
Summary: Geometric effects associated with the relative size of the R-site atom in infinite-layer nickelates RNiO2 are investigated via first-principles calculations. The study reveals that the size of the R-site atom plays a crucial role in determining the electronic structure and structural transformation in the materials.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Chemistry, Physical
Kerstin Wissel, Fabio Bernardini, Heesu Oh, Sami Vasala, Roland Schoch, Bjoern Blaschkowski, Pieter Glatzel, Matthias Bauer, Oliver Clemens, Andres Cano
Summary: Understanding high-temperature unconventional superconductivity has always been a long-standing problem, with cuprates as central reference materials. The recent discovery of superconductivity in analogous nickelate thin films marks a fundamental breakthrough, calling for the search of additional materials in this class. In this study, a new single-layer T' Pr2NiO3F compound was synthesized and compared with the previously synthesized T' nickelate La2NiO3F. The electronic properties of the R2NiO3F series (R = La-Lu) were analyzed using first-principles calculations. The mixed anion systems were found to have a high degree of stability, and their composition could be finely tuned through synthesis. Furthermore, these unprecedented square-planar nickelates show great promise as potential superconductors due to their exceptional electronic structure.
CHEMISTRY OF MATERIALS
(2022)
Article
Physics, Applied
Viktor V. Chabanenko, Adam Nabialek, Roman Puzniak, Volodymyr F. Rusakov
Summary: Observations were made on the variations in flux penetration into doubly connected bulk superconductors (hollow cylinder, ring) and singularly connected discs using thermomagnetic avalanches. Transformation of the disc into a ring resulted in significant changes in stability, increasing the magnetic field instability region in the ring and the number of thermomagnetic avalanches. Flux jump duration, amount of flux entering the sample, and magnetic field dependence also changed, with the weak linear field dependence in the disc being inversely proportional to the magnetic field in the ring. The study also revealed a complex fine structure of magnetic flux penetrating the ring hole and a sharp increase in the speed of avalanche flux front when flux appeared in the hole.
SUPERCONDUCTOR SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Physical
Nikolai D. Zhigadlo, Roman Puzniak, Philip J. W. Moll, Fabio Bernardini, Toni Shiroka
Summary: We present a study on the electronic properties of LaFeAsO single crystals co-substituted with Sm and P, both in normal and superconducting states. The appearance of superconductivity is believed to be caused by the inner chemical pressure induced by the smaller-size isovalent substituents. The results demonstrate the potential of co-substitution as a method to induce superconductivity in the 1111 family, opening up new possibilities for the design and creation of superconductors through chemical manipulation.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
E. E. Zubov, I. Fita, R. Puzniak, A. Wisniewski
Summary: A model of nonequilibrium thermodynamics of erbium orthoferrite is presented, considering the quantum-mechanical effects related to arbitrary magnetic fields and anisotropic exchange interactions. Possible mechanisms for the exchange bias of magnetic hysteresis loops are proposed based on recent experimental data. The competitive character of exchange interactions in erbium orthoferrite is determined.
Article
Chemistry, Multidisciplinary
Lama Khalil, Cyrine Ernandes, Jose Avila, Adrien Rousseau, Pavel Dudin, Nikolai D. Zhigadlo, Guillaume Cassabois, Bernard Gil, Fabrice Oehler, Julien Chaste, Abdelkarim Ouerghi
Summary: In this study, we demonstrate the stable growth of p-type hexagonal boron nitride (h-BN) by using Mg atoms as substitutional impurities. Our experiments involving micro-Raman spectroscopy, nano-ARPES, and KPFM show that Mg-doping significantly alters the electronic properties of h-BN. The Mg dopants shift the valence band maximum and result in a reduced Fermi level difference between pristine and Mg-doped h-BN crystals. This research establishes Mg-doping as a promising method for high-quality p-type doped h-BN films, which are crucial for applications in deep ultraviolet LEDs and wide bandgap optoelectronic devices.
NANOSCALE ADVANCES
(2023)
Article
Engineering, Electrical & Electronic
Andrea Motroni, Fabio Bernardini, Alice Buffi, Paolo Nepa, Bernardo Tellini
Summary: This paper presents a UHF-RFID robotic system that can be used for inventory and localization of tagged items. The system reconstructs the robot's trajectory using a sensor-fusion method and leverages it to localize target tags through a multi-antenna synthetic-aperture-radar approach. Experimental results demonstrate the feasibility and performance of the system.
IEEE JOURNAL OF RADIO FREQUENCY IDENTIFICATION
(2022)
Article
Materials Science, Multidisciplinary
I. Fita, R. Puzniak, E. E. Zubov, P. Iwanowski, A. Wisniewski
Summary: The compensated ferrimagnet orthoferrite ErFeO3 exhibits temperature-driven spin switching and exchange bias, which is manifested as the temperature shift of the hysteresis loops upon cooling and heating. The unidirectional exchange bias anisotropy is caused by the shift in the region of coexistence of negative and positive magnetization, determined by the applied magnetic field. This phenomenon is discussed within a model that explains the magnetic compensation mechanism in ErFeO3.
Article
Materials Science, Multidisciplinary
T. Zajarniuk, A. Szewczyk, P. Wisniewski, M. U. Gutowska, R. Puzniak, H. Szymczak, I Gudim, V. A. Bedarev, M. Pashchenko, P. Tomczak, W. Szuszkiewicz
Summary: The specific heat of a TbAl3(BO3)(4) crystal was studied, and a phase transition was found at low temperatures. The results showed that an increase in magnetic field can lower the transition temperature, and the specific heat and Gruneisen ratio exhibited characteristics of a quantum critical point. By constructing a phase diagram and assessing the critical exponent, the nature of the system was revealed. Magnetization studies indicated ferromagnetic ordering, but contrary to classical behavior, suggesting a dominant role of quantum fluctuations in the phase transition.