Article
Physics, Multidisciplinary
Jean-Come Philippe, Alexis Lespinas, Jimmy Faria, Anne Forget, Dorothee Colson, Sarah Houver, Maximilien Cazayous, Alain Sacuto, Indranil Paul, Yann Gallais
Summary: Anisotropic strain selectively affects the role of nematic fluctuations in promoting superconductivity. Our results confirm the significance of nematic fluctuations in electron pairing.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Condensed Matter
Zhen-kai Xie, Xu Chen, Jian-gang Guo
Summary: In this study, we report the structure, electrical and magnetic properties of Ba(Mn1-xCrx)(2)As-2 and Ba0.8K0.2(Mn1-xCrx)(2)As-2 compounds. By doping Cr in the BaMn2As2 semiconductor, the resistivity can be greatly decreased without changing the structural symmetry. XPS and Hall measurements show that the doped Cr has a valence state of +3, which effectively introduces electron carriers. Additionally, a magnetic transition is observed at low temperature, originating from the change in spin re-orientation from ideal antiferromagnetic to canted antiferromagnetic state.
PHYSICA B-CONDENSED MATTER
(2022)
Article
Materials Science, Multidisciplinary
Qiang Zou, Mingming Fu, Zhiming Wu, Li Li, David S. Parker, Athena S. Sefat, Zheng Gai
Summary: Electronic inhomogeneities in Co, Ni, and Cr doped BaFe2As2 single crystals were compared in different bulk property regions. Machine learning was used to categorize the inhomogeneous electronic states, revealing different origins and roles. While the relative percentages of electronic states varied in different samples, the total volume fractions were similar.
NPJ QUANTUM MATERIALS
(2021)
Article
Physics, Multidisciplinary
Haruyasu Sato, Mitsuhiro Akatsu, Ryosuke Kurihara, Yoshiaki Kobayashi, Yuichi Nemoto
Summary: The critical properties originating from degenerate orbitals at the ferro-quadrupole quantum critical point (QCP) in the iron pnictide superconductor Ba(Fe1-xCox)2As2 were investigated through ultrasonic experiments. The temperature dependence of various parameters, such as the elastic soft mode C66, Jahn-Teller energy Delta Q, Weiss temperature Theta Q, and hexadecapole susceptibility ultrasonic attenuation coefficient alpha 66, near the QCP were found to exhibit significant changes. The unconventional critical exponent z nu was observed to be 3 near the QCP, suggesting enhanced quantum fluctuations. These observations indicate the potential key role of order parameter fluctuations in the superconductivity.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2023)
Article
Materials Science, Multidisciplinary
Jaafar N. Ansari, Karen L. Sauer, Igor I. Mazin
Summary: In this study, the effect of Co doping on the real-space nematic fluctuations in BaFe2As2 is investigated by combining nuclear magnetic resonance data with first-principles calculations. It is found that the dynamics of nematic fluctuations are exceptionally slow even in the formally tetragonal phase.
Article
Chemistry, Physical
Yusuke Shimada, Shinnosuke Tokuta, Akinori Yamanaka, Akiyasu Yamamoto, Toyohiko J. Konno
Summary: This study reports the critical current density (J(c)) and three-dimensional microstructure of polycrystalline bulk Co-doped Ba122 superconductors with highly dense grain boundaries. The anomalous growth of secondary particles and the inter-aggregation structures were found to be significantly different in samples with finer grains, potentially extrinsically limiting J(c). These important micro-structural features were quantified using two parameters - local thickness and total pore length - by reconstructing the three-dimensional structure of the superconducting phase. The results emphasize the importance of understanding and controlling the micro-structural formation process for improving the J(c) properties of 122 polycrystalline materials consisting of ultrafine grains.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Physical
Nikita Snegirev, Igor Lyubutin, Anton Kulikov, Denis Zolotov, Alexandre Vasiliev, Marianna Lyubutina, Sergey Yagupov, Yuliya Mogilenec, Kira Seleznyova, Mark Strugatsky
Summary: A series of Fe1-xGaxBO3 single crystals were grown by the flux technique and their atomic structure was investigated by high-resolution electron microscopy. Comparing the experimental and calculated data for crystals of the extreme members of the series with the mixed crystals revealed a slight decrease in structural perfection due to partial isomorphic substitution. Each sample studied contains regions free of defects and stresses.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Engineering, Electrical & Electronic
Shoya Sakamoto, Guoqiang Zhao, Goro Shibata, Zheng Deng, Kan Zhao, Xiancheng Wang, Yosuke Nonaka, Keisuke Ikeda, Zhendong Chi, Yuxuan Wan, Masahiro Suzuki, Tsuneharu Koide, Arata Tanaka, Sadamichi Maekawa, Yasutomo J. Uemura, Changqing Jin, Atsushi Fujimori
Summary: The study investigates the perpendicular magnetic anisotropy of a layered ferromagnetic semiconductor using angle-dependent X-ray magnetic circular dichroism measurements. The large magnetic anisotropy is attributed to the anisotropic distribution of Mn 3d electrons and the lifting of degeneracy of p-d(xz), d(yz) hybridized states.
ACS APPLIED ELECTRONIC MATERIALS
(2021)
Article
Engineering, Electrical & Electronic
Meng-Jing Jiang, Hui-Li Tian, Yu-Long Hai, Ning Lu, Pei-Fei Tong, Shuang-Yuan Wu, Wen-Jie Li, Chun-Lei Yang, Guo-Hua Zhong
Summary: Based on first-principles calculations, it was found that the ternary hydride Ba-x(CH4)(1-x) may exhibit metallization and superconductivity at low pressures, suggesting that metal-doped methane could be a potential candidate for searching high-temperature superconductors under low pressures.
ACS APPLIED ELECTRONIC MATERIALS
(2021)
Article
Engineering, Electrical & Electronic
Tayebeh Mousavi, Yunhua Shi, John Durrell, Chris Grovenor, Susannah Speller
Summary: Bulk rare earth-Ba-cuprate superconductors have the potential to generate high-strength trapped magnetic fields, and the choice of rare earth element plays a crucial role in the growth and microstructure of single grains.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2022)
Article
Materials Science, Multidisciplinary
Teklie Lissanu Tegegne, Gebregziabher Kahsay
Summary: This study investigated the mathematical expressions of temperature and angle dependence of magnetic fields and Ginzburg-Landau characteristics in iron-based superconductors. Phase diagrams were plotted based on experimental values, showing the relationship between various parameters with temperature and angle variations. The theoretical investigation was found to be consistent with the obtained experimental results.
JOURNAL OF MAGNETICS
(2021)
Article
Chemistry, Physical
E. N. Zanaeva, D. A. Milkova, A. Bazlov, E. Ubyivovk, N. Yu Tabachkova, A. Yu Churyumov, A. Inoue
Summary: The glassy phase in (Fe1-xNix)(79)B12P5Si3C1 alloy ribbons exhibits good bending plasticity and Ni-containing glassy alloys show multistage crystallization with different activation energies. The 0.5Ni glassy alloy stands out with the largest SCL region, good soft magnetic properties, and complex crystallization processes. The development of medium-range ordered atomic configurations in the 0.5Ni alloy contributes to its enhanced magnetic softness and lower internal stress state.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Engineering, Electrical & Electronic
Zheyu Zhang, Tahmineh Mahmoudi, Yeon Ho Im, Yoon-Bong Hahn
Summary: In this study, the optical and electrical properties of alloyed Ba x Sn1-x O2-x (BSO) were modulated by adjusting the Ba:Sn ratio. It was found that increasing the Ba content in BSO led to a decrease in both the bandgap and electron mobility of BSO films. This suggests that the electron mobility of BSO-based electron transport layers in optoelectronic devices can be easily controlled by adjusting the Ba:Sn ratio. The bandgap and electron mobility of BSO films ranged from 3.02 to 3.71 eV and from 5.2 x 10(-3) to 9.8 x 10(-3) cm(2)/V, respectively.
ACS APPLIED ELECTRONIC MATERIALS
(2023)
Article
Chemistry, Physical
E. A. Nazimudeen, T. E. Girish, Sunila Abraham, C. V. Midhun, K. M. Varier
Summary: The effects of irradiation using high-energy electrons and X-rays on cast speculum metal mirrors are studied in detail for the first time. The irradiation causes significant microstructural and morphological changes on the surface of the metal, leading to modifications in surface properties and reflectivity. The electron beam irradiation has a greater impact on surface topography and crystallographic properties at 6 MeV than at 9 MeV.
RADIATION PHYSICS AND CHEMISTRY
(2023)
Article
Physics, Condensed Matter
Xiande Zheng, Muhammad Asim Farid, Xiaoge Wang, Yan Wang, Jinling Geng, Fuhui Liao, Junliang Sun, Guobao Li, Laijun Liu, Jianhua Lin
Summary: Magnesium is doped into BaBi0.25Pb0.75O3-delta to form a solid solution Ba (Bi0.25Pb0.75)(1-x)MgxO3-delta (0 <= x <= 0.10) via solid-state reaction. X-ray, neutron, and selected area electron diffraction confirm its crystallization in triclinic space group P1. The increased oxygen vacancies with Mg are responsible for the unit cell volume increase, resulting in the superconductivity of the samples with T-C(zero) between 11.2 and 9.2 K.
SOLID STATE COMMUNICATIONS
(2023)
Article
Physics, Condensed Matter
Ruslan Prozorov, Sergey L. Bud'ko, Paul C. Canfield
Summary: This study reports the observation of rectangular cross-section tubular ferromagnetic domains in thick single crystals of CeAgSb2 in zero applied field. The formation of closed-topology patterns is facilitated by the relatively low exchange energy, small net magnetic moment, and anisotropic in-plane crystal electric fields. The tubular domain structure irreversibly transforms into a dendritic pattern upon cycling the magnetic field, resulting in a 'topological magnetic hysteresis'.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2022)
Article
Chemistry, Physical
Gianluca Ghigo, Michela Fracasso, Roberto Gerbaldo, Laura Gozzelino, Francesco Laviano, Andrea Napolitano, Guang-Han Cao, Michael J. Graf, Ruslan Prozorov, Tsuyoshi Tamegai, Zhixiang Shi, Xiangzhuo Xing, Daniele Torsello
Summary: A microwave technique for investigating the AC magnetic susceptibility of small samples in the GHz frequency range is presented. The method utilizes a coplanar waveguide resonator and allows for measuring the absolute value of the complex susceptibility. Several iron-based superconducting systems, including the 11, 122, 1144, and 12442 families, were characterized. The effects of different types of doping and proton irradiation were studied, and the magnetic superconductor EuP-122, which exhibits both superconducting and ferromagnetic transitions, was discussed.
Article
Multidisciplinary Sciences
J. Lim, A. C. Hire, Y. Quan, J. S. Kim, S. R. Xie, S. Sinha, R. S. Kumar, D. Popov, C. Park, R. J. Hemley, Y. K. Vohra, J. J. Hamlin, R. G. Hennig, P. J. Hirschfeld, G. R. Stewart
Summary: High-pressure electrical resistivity measurements and theoretical calculations reveal that superconductivity can be induced in ultra-hard WB2 during compression, originating from the formation of metastable stacking faults and twin boundaries. The appearance of superconductivity is not accompanied by a structural transition, but instead correlated with the formation and percolation of mechanically-induced stacking faults and twin boundaries, as confirmed by synchrotron x-ray diffraction measurements.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Physical
Kyuil Cho, Marcin Konczykowski, Makariy A. Tanatar, Igor I. Mazin, Yong Liu, Thomas A. Lograsso, Ruslan Prozorov
Summary: Low-temperature variable-energy electron irradiation induced non-magnetic disorder in a hole-doped iron-based superconductor Ba1-xKxFe2As2, x = 0.80. The resistivity of the sample increased linearly with irradiation fluence, indicating the creation of uncorrelated dilute point-like disorder. The predominant creation of defects in the iron sublattice was confirmed by comparing with calculated partial cross-sections. Simultaneously, the superconducting transition temperature was monotonically suppressed due to the total scattering rate, supporting the assumption of the dominant role of the iron sub-lattice in iron-based superconductors.
Article
Materials Science, Multidisciplinary
Brinda Kuthanazhi, Kamal R. Joshi, Sunil Ghimire, Erik Timmons, Elena Gati, Li Xiang, Ruslan Prozorov, Sergey L. Bud'ko, Paul C. Canfield
Summary: EuCd2As2 is an antiferromagnetic semimetal that can undergo changes in its magnetic state and properties through Ag and Na doping. Temperature-substitution phase diagrams were constructed and showed the splitting of the magnetic transition into two different transitions. It was observed that Ag and Na doping stabilized a magnetic state with a net ferromagnetic moment. This study demonstrates that chemical substitution and changes in band filling can be used to tune the magnetic ground state and stabilize a ferromagnetic phase in EuCd2As2.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Physics, Multidisciplinary
K. Ishihara, M. Kobayashi, K. Imamura, M. Konczykowski, H. Sakai, P. Opletal, Y. Tokiwa, Y. Haga, K. Hashimoto, T. Shibauchi
Summary: The exotic superconducting properties of the paramagnetic spin-triplet superconductor candidate UTe2, such as extremely high upper critical field and possible chiral superconducting states, have attracted significant attention. This study focuses on the thermodynamic critical field Hc, the lower critical field Hc1, and the upper critical field Hc2 at low fields of ultraclean single crystals of UTe2, providing crucial insight into its intrinsic superconducting properties. Anomalous enhancement of Hc1 values with magnetic field along the b and c axes, showing unusual low-temperature upturns, is attributed to the effect of strong Ising-like ferromagnetic fluctuations on the vortex line energy.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Materials Science, Multidisciplinary
Mainak Pal, Andreas Kreisel, P. J. Hirschfeld
Summary: There are proposals for platforms supporting topological superconductivity in high-temperature superconductors in order to take advantage of the larger superconducting gap and the expected robustness of Majorana zero modes. The iron-based materials offer large Tc and nodeless energy gaps, along with atomically flat surfaces that allow for engineering defect structures and measuring spectroscopic properties to reveal topological aspects. By including the correlated nature of materials and the multiband electronic structure, the authors demonstrate how correlations can lead to local magnetic order and the emergence of a topological superconducting state.
Article
Materials Science, Multidisciplinary
Mainak Pal, Andreas Kreisel, W. A. Atkinson, P. J. Hirschfeld
Summary: Theoretical studies of disordered d-wave superconductors have mainly focused on optimally doped models with strong scatterers, but it is necessary to also study the weaker scattering associated with dopant atoms in order to address recent controversies about overdoped cuprates. In this study, simple models of such systems are investigated using the self-consistent Bogoliubov-de Gennes (BdG) framework and compared to disorder-averaged results using the self-consistent T-matrix-approximation (SCTMA). The SCTMA performs well overall, except for highly disordered systems with strongly suppressed superfluid density.
Article
Materials Science, Multidisciplinary
Vivek Mishra, Yu Li, Fu-Chun Zhang, Stefan Kirchner
Summary: We investigate the effect of spin-orbit coupling on proximity-induced superconductivity in a normal metal attached to a superconductor. Specifically, we consider a heterostructure with Rashba spin-orbit coupling due to the presence of interfaces. The properties of the induced superconductivity and the effect of impurity scattering are addressed within the tunneling Hamiltonian formalism, with the finding of a mixture of singlet and triplet pairing.
Article
Chemistry, Multidisciplinary
Shao-Pin Chiu, Vivek Mishra, Yu Li, Fu-Chun Zhang, Stefan Kirchner, Juhn-Jong Lin
Summary: We observe enhanced interfacial two-component superconductivity with a dominant triplet component in nonmagnetic CoSi2/TiSi2 superconductor/normal-metal planar heterojunctions. This is achieved by detecting odd-frequency spin-triplet even-parity Cooper pairs in the diffusive normal-metal part of T-shaped proximity junctions. The transition temperature enhancement can be tuned by up to a factor of 2.3 and the upper critical field increases by up to a factor of 20 by modifying the diffusivity of the normal-metal part. The findings are attributed to the C49 phase of TiSi2 stabilized in confined geometries and are supported by a Ginzburg-Landau model and the quasi-classical theory. Our results are also relevant to the enigmatic 3-K phase reported in Sr-2 RuO4.
Article
Materials Science, Multidisciplinary
Elina Zhakina, Philippa H. McGuinness, Markus Koenig, Romain Grasset, Maja D. Bachmann, Seunghyun Khim, Carsten Putzke, Philip J. W. Moll, Marcin Konczykowski, Andrew P. Mackenzie
Summary: High-energy electron irradiation is used to study the effects on PtCoO2, and it is found that this technique can transition from nonlocal to local transport behavior, thus determining the nature and extent of unconventional transport regimes.
Article
Materials Science, Multidisciplinary
Philip M. Dee, Benjamin Cohen-Stead, Steven Johnston, P. J. Hirschfeld
Summary: In a recent study, Schrodi et al. discovered an unconventional superconducting state with a sign-changing order parameter using the Migdal-Eliashberg theory. They found this unconventional solution despite using an isotropic bare electron-phonon coupling in the Hamiltonian. However, our Monte Carlo simulations on a similar model suggest that unconventional pairing correlations do not exceed their noninteracting values at any carrier concentration we have checked. Instead, strong charge-density-wave correlations persist at the lowest accessible temperatures.
Article
Materials Science, Multidisciplinary
J. Sitnicka, M. Konczykowski, K. Sobczak, P. Skupinski, K. Grasza, Z. Adamus, A. Reszka, A. Wolos
Summary: This study focuses on the magnetic coupling mechanisms in magnetically doped topological insulators (TIs) and investigates the role of bulk carriers and the effect of Fermi level tuning on magnetism and magnetotransport. The results show that the quantum anomalous Hall effect (AHE) can be effectively managed, maximized, or turned off by adjusting the Fermi level position.
Article
Materials Science, Multidisciplinary
H. U. Ozdemir, Vivek Mishra, N. R. Lee-Hone, Xiangru Kong, T. Berlijn, D. M. Broun, P. J. Hirschfeld
Summary: Recent experimental papers suggest the breakdown of the quasiparticle-based Landau-BCS paradigm in the superconducting state due to unexpected behavior. However, the authors argue that a phenomenological dirty d-wave theoretical analysis can explain most aspects of the superconducting state by considering the unusual effects of weak, out-of-plane dopant impurities. In this study, ab initio calculations were performed to quantitatively analyze the theory by considering realistic band structures, Fermi liquid renormalizations, and vertex corrections.
Article
Materials Science, Multidisciplinary
Kyuil Cho, M. Konczykowski, S. Teknowijoyo, S. Ghimire, M. A. Tanatar, Vivek Mishra, R. Prozorov
Summary: In this study, controlled artificial disorder was induced in a high-quality optimally doped YBa2Cu3O7-δ single crystal using electron irradiation, causing a significant suppression of the superconductor's critical temperature and a transition in the low-temperature behavior of the London penetration depth λ(T). The evolution of the superfluid density was analyzed by varying the amount and strength of nonmagnetic scattering, providing insights into the scattering potential strength and phase shift.
