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Articles 1 - 10 of 10
Full-Text Articles in Physical Sciences and Mathematics
Tuning Superconductivity In Fese Thin Films Via Magnesium Doping, Wenbin Qiu, Zongqing Ma, Yongchang Liu, Md Shahriar Hossain, Xiaolin Wang, Chuanbing Cai, S X. Dou
Tuning Superconductivity In Fese Thin Films Via Magnesium Doping, Wenbin Qiu, Zongqing Ma, Yongchang Liu, Md Shahriar Hossain, Xiaolin Wang, Chuanbing Cai, S X. Dou
Australian Institute for Innovative Materials - Papers
In contrast to its bulk crystal, the FeSe thin film or layer exhibits better superconductivity performance, which recently attracted much interest in its fundamental research as well as in potential applications around the world. In the present work, tuning superconductivity in FeSe thin films was achieved by magnesium-doping technique. Tc is significantly enhanced from 10.7 K in pure FeSe films to 13.4 K in optimized Mg-doped ones, which is approximately 1.5 times higher than that of bulk crystals. This is the first time achieving the enhancement of superconducting transition temperature in FeSe thin films with practical thickness (120 nm) via …
Interface-Enhanced Electron-Phonon Coupling And High-Temperature Superconductivity In Potassium-Coated Ultrathin Fese Films On Srtio3, Chenjia Tang, Chong Liu, Guanyu Zhou, Fangsen Li, Hao Ding, Zhi Li, Ding Zhang, Zheng Li, Canli Song, Shuaihua Ji, Ke He, Lili Wang, Xucan Ma, Qi-Kun Xue
Interface-Enhanced Electron-Phonon Coupling And High-Temperature Superconductivity In Potassium-Coated Ultrathin Fese Films On Srtio3, Chenjia Tang, Chong Liu, Guanyu Zhou, Fangsen Li, Hao Ding, Zhi Li, Ding Zhang, Zheng Li, Canli Song, Shuaihua Ji, Ke He, Lili Wang, Xucan Ma, Qi-Kun Xue
Australian Institute for Innovative Materials - Papers
Alkali-metal (potassium) adsorption on FeSe thin films with thickness from 2 unit cells (UC) to 4 UC on SrTiO3 grown by molecular beam epitaxy is investigated with a low-temperature scanning tunneling microscope. At appropriate potassium coverage (0.20-0.25 monolayer), the tunneling spectra of the films all exhibit a superconductinglike gap which is overall larger than 11 meV (five times the gap value of bulk FeSe) and decreases with increasing thickness, and two distinct features of characteristic phonon modes at ∼11 and ∼21 meV. The results reveal the critical role of the interface-enhanced electron-phonon coupling for possible high-temperature superconductivity in ultrathin FeSe …
Improvement In Structure And Superconductivity Of Bulk Fese0.5te0.5 Superconductors By Optimizing Sintering Temperature, Ning Chen, Yongchang Liu, Zongqing Ma, Liming Yu, Huijun Li
Improvement In Structure And Superconductivity Of Bulk Fese0.5te0.5 Superconductors By Optimizing Sintering Temperature, Ning Chen, Yongchang Liu, Zongqing Ma, Liming Yu, Huijun Li
Australian Institute for Innovative Materials - Papers
Sintering temperature plays a vital role in the evolution of phase structure and microstructure in polycrystalline FeSe0.5Te0.5 bulks fabricated by the two-step sintering method, and thus significantly influences their superconducting properties. Elevated sintering temperature (600-700°C) at second step facilitates the substitution of Te into the superconducting phase, which leads to the increased lattice distortion and thus contributes to the enhancement of superconductivity (the value of Tc reaches 15.6K). At the same time, the accelerated growth of the superconducting grains and the improved homogeneity motivated by elevated sintering temperature serve as the main reason for the sharp superconducting transition.
Visualizing Superconductivity In Fese Nanoflakes On Srtio3 By Scanning Tunneling Microscopy, Zhi Li, Jun-Ping Peng, Hui-Min Zhang, Canli Song, Shuaihua Ji, Lili Wang, Ke He, Xiaowei Chen, Qi-Kun Xue, Xu-Cun Ma
Visualizing Superconductivity In Fese Nanoflakes On Srtio3 By Scanning Tunneling Microscopy, Zhi Li, Jun-Ping Peng, Hui-Min Zhang, Canli Song, Shuaihua Ji, Lili Wang, Ke He, Xiaowei Chen, Qi-Kun Xue, Xu-Cun Ma
Australian Institute for Innovative Materials - Papers
Scanning tunneling microscopy and spectroscopy have been employed to investigate the superconductivity in single unit-cell FeSe nanoflakes on SrTiO3 substrates. We find that the differential conductance dI/dV spectra are spatially nonuniform and fluctuate within the flakes as their area is reduced to below ∼150 nm2. An enhancement in the superconductivity-related gap size as large as 25% is observed. The superconductivity behavior disappears when the FeSe nanoflakes reduce to ∼40 nm2. Compared to a previous report [Wang et al., Chin. Phys. Lett. 29, 037402 (2012)], the gap is asymmetric relative to the Fermi energy EF. All the features, particularly the fluctuating …
Dichotomy Of The Electronic Structure And Superconductivity Between Single-Layer And Double-Layer Fese/Srtio3 Films, Xu Liu, Defa Liu, Wenchao Zhang, Junfeng He, Lin Zhao, Shaolong He, Daixiang Mou, Fangsen Li, Chenjia Tang, Zhi Li, Lili Wang, Yingying Peng, Yan Liu, Chaoyu Chen, Guodong Liu, Xiaoli Dong, Jun Zhang, Chuangtian Chen, Zuyan Xu, Xi Chen, Xu-Cun Ma, Qi-Kun Xue, X J. Zhou
Dichotomy Of The Electronic Structure And Superconductivity Between Single-Layer And Double-Layer Fese/Srtio3 Films, Xu Liu, Defa Liu, Wenchao Zhang, Junfeng He, Lin Zhao, Shaolong He, Daixiang Mou, Fangsen Li, Chenjia Tang, Zhi Li, Lili Wang, Yingying Peng, Yan Liu, Chaoyu Chen, Guodong Liu, Xiaoli Dong, Jun Zhang, Chuangtian Chen, Zuyan Xu, Xi Chen, Xu-Cun Ma, Qi-Kun Xue, X J. Zhou
Australian Institute for Innovative Materials - Papers
The latest discovery of possible high-temperature superconductivity in the single-layer FeSe film grown on a SrTiO3 substrate has generated much attention. Initial work found that, while the single-layer FeSe/SrTiO3 film exhibits a clear signature of superconductivity, the double-layer film shows an insulating behaviour. Such a marked layer-dependent difference is surprising and the underlying origin remains unclear. Here we report a comparative angleresolved photoemission study between the single-layer and double-layer FeSe/SrTiO3 films annealed in vacuum. We find that, different from the single-layer FeSe/SrTiO3 film, the double-layer FeSe/SrTiO3 film is hard to get doped and remains in the semiconducting/ insulating state under …
Interface Charge Doping Effects On Superconductivity Of Single-Unit-Cell Fese Films On Srtio3 Substrates, Wenhao Zhang, Zhi Li, Fangsen Li, Huimin Zhang, Jun-Ping Peng, Chenjia Tang, Qingyan Wang, Ke He, Xi Chen, Lili Wang, Xu-Cun Ma, Qi-Kun Xue
Interface Charge Doping Effects On Superconductivity Of Single-Unit-Cell Fese Films On Srtio3 Substrates, Wenhao Zhang, Zhi Li, Fangsen Li, Huimin Zhang, Jun-Ping Peng, Chenjia Tang, Qingyan Wang, Ke He, Xi Chen, Lili Wang, Xu-Cun Ma, Qi-Kun Xue
Australian Institute for Innovative Materials - Papers
We prepare single-unit-cell FeSe films on insulating SrTiO3 substrates by molecular beam epitaxy and investigate the evolution of their superconducting properties with annealing by in situ scanning tunneling microscopy and scanning tunneling spectroscopy and ex situ transport measurements. We find that through an annealing process, the superconductivity of 1-uc FeSe films on SrTiO3 substrates develops with the formation of stoichiometric FeSe films and is further enhanced by charge transfer from SrTiO3 substrates to FeSe films. Moreover, the superconductivity is independent of the bulk property of the SrTiO3 substrate, regardless of whether it is insulating or conductive. Our results reveal that …
Magnetic Phase Diagram And Correlation Between Metamagnetism And Superconductivity In Ru0.9sr2ycu2.1o7.9, Rashmi Nigam, Shane J. Kennedy, Alexey V. Pan, S X. Dou
Magnetic Phase Diagram And Correlation Between Metamagnetism And Superconductivity In Ru0.9sr2ycu2.1o7.9, Rashmi Nigam, Shane J. Kennedy, Alexey V. Pan, S X. Dou
Australian Institute for Innovative Materials - Papers
The magnetic superconductor Ru0.9Sr2YCu2.1O7.9 (Ru-1212Y) has been investigated using neutron diffraction under variable temperature and magnetic field. With the complementary information from magnetization measurements, we propose a magnetic phase diagram T-H for the Ru-1212 system. Uniaxial antiferromagnetic (AFM) order of 1.2μ B/Ru atoms with moments parallel to the c-axis is found below the magnetic transition temperature at ~140 K in the absence of magnetic field. In addition, ferromagnetism (FM) in the ab-plane develops below ~120 K, but is suppressed at lower temperature by superconducting correlations. Externally applied …
Evaluation Of Mg Size Dependence On Superconductivity Of Mgb2, B.B Sinha, Seok Hem Jang, K C. Chung, Jung Ho Kim, S X. Dou
Evaluation Of Mg Size Dependence On Superconductivity Of Mgb2, B.B Sinha, Seok Hem Jang, K C. Chung, Jung Ho Kim, S X. Dou
Australian Institute for Innovative Materials - Papers
MgB2 bulk samples are synthesized through solid state reaction route using Mg precursors with different particle size by keeping the boron precursor unchanged. Scanning electron microscopy study of the fractured surface for all the samples depicts quite distinct structure depending on the Mg precursor. Big size of Mg precursor resulted in to largely elongated and deep pores while smaller one gave roughly ellipsoidal and shallow pore structure. Influence of the Mg particle size on the grain to grain connectivity reflected in the critical current density value which was greater for samples with smaller Mg precursor. All the synthesized samples …
Molecular-Beam Epitaxy And Robust Superconductivity Of Stoichiometric Fese Crystalline Films On Bilayer Graphene, Canli Song, Yi-Lin Wang, Yeping Jiang, Zhi Li, Lili Wang, Ke He, Xi Chen, Xu-Cun Ma, Qi-Kun Xue
Molecular-Beam Epitaxy And Robust Superconductivity Of Stoichiometric Fese Crystalline Films On Bilayer Graphene, Canli Song, Yi-Lin Wang, Yeping Jiang, Zhi Li, Lili Wang, Ke He, Xi Chen, Xu-Cun Ma, Qi-Kun Xue
Australian Institute for Innovative Materials - Papers
We report on molecular beam epitaxy growth of stoichiometric and superconducting FeSe crystalline thin films on double-layer graphene. Layer-by-layer growth of high-quality films has been achieved in a well-controlled manner by using Se-rich condition, which allow us to investigate the thickness-dependent superconductivity of FeSe. In situ low-temperature scanning tunneling spectra reveal that the local superconducting gap in the quasiparticle density of states is visible down to two triple layers for the minimum measurement temperature of 2.2 K, and that the transition temperature Tc scales inversely with film thickness.
Superconductivity In Smfe1-Xcoxaso (X=0.0-0.30), V P. Awana, Anand Pal, Arpita Vajpayee, R S. Meena, H Kishan, Mushahid Husain, Rong Zeng, S Yu, K Yamaura, E Takayammuromachi
Superconductivity In Smfe1-Xcoxaso (X=0.0-0.30), V P. Awana, Anand Pal, Arpita Vajpayee, R S. Meena, H Kishan, Mushahid Husain, Rong Zeng, S Yu, K Yamaura, E Takayammuromachi
Australian Institute for Innovative Materials - Papers
We report synthesis, structural details, and magnetization of SmFe1-xCoxAsO with x ranging from 0.0 to 0.30. It is found that Co substitutes fully at Fe site in SmFeAsO in an isostructural lattice with slightly compressed cell. The parent compound exhibited known as the spin density wave (SDW) character is below at around 140 K. Successive doping of Co at Fe site suppressed the SDW transition for x=0.05 and later induced superconductivity for x=0.10, 0.15, and 0.20, respectively, at 14, 15.5, and 9 K. The lower critical field as seen from magnetization measurements is below 200 Oe. …