scholarly journals Superconducting properties of very high quality NbN thin films grown by pulsed laser deposition

2019 ◽  
Vol 70 (7) ◽  
pp. 89-94
Author(s):  
Serhii Volkov ◽  
Maros Gregor ◽  
Tomas Roch ◽  
Leonid Satrapinskyy ◽  
Branislav Grančič ◽  
...  
Keyword(s):  
Thin Films ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Pulsed Laser ◽  
Domain Size ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
Si Substrate ◽  
Coherent Domain Size ◽  
Coherent Domain

Abstract In this work, we study the effect of the various substrates on the growth and superconducting properties of NbN thin films grown by using pulsed laser ablation in a N2 + 1%H2 atmosphere on MgO, Al2O3 and Si substrates. Structural and superconducting analyses of the films demonstrate that using MgO and Al2O3 substrates can significantly improve the film properties compared to Si substrate. The X-ray diffraction data indicate that MgO and Al2O3 substrates produce highly oriented superconducting NbN films with large coherent domain size in the out-of plane direction on the order of layer thickness and with a superconducting transition temperature of 13.1 K and 15.2 K, respectively. On the other hand, the NbN film grown on the Si substrate exhibits random polycrystalline orientation. Together with the smallest coherent domain size it leads to the lower critical temperature of 8.3 K. Finally, by using a passivation surface layer we are able to improve superconducting properties of NbN thin film and we observe superconducting transition temperature 16.6 K, the one of the highest value reported so far for 50 nm thick NbN film on sapphire.

scholarly journals Distinct superconducting properties and hydrostatic pressure effects in 2D α- and β-Mo2C crystal sheets

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Yunjie Fan ◽  
Chuan Xu ◽  
Xiang Liu ◽  
Chao Ma ◽  
Yuewei Yin ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Hydrostatic Pressure ◽  
Electronic Properties ◽  
Superconducting Transition Temperature ◽  
Important Influence ◽  
Pressure Effects ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
Disordered Carbon

Abstract Recently, 2D Mo2C, a new member of the MXene family, has attracted much attention due to the exotic superconducting properties discovered in 2D α-Mo2C. Here, not only 2D α-Mo2C but also 2D β-Mo2C crystal sheets with distinct disordered carbon distributions were successfully grown. 2D β-Mo2C shows a much stronger superconductivity than 2D α-Mo2C, and their superconductivities have different hydrostatic pressure responses. The superconducting transition temperature Tc of 2D α-Mo2C shows a dome-shaped profile under pressure, implying the existence of two competing effects arising from phononic and electronic properties, while for 2D β-Mo2C, Tc decreases monotonically with increasing pressure, possibly due to phonon stiffening. These results indicate that the electronic properties have a more important influence on the superconductivity in 2D α-Mo2C compared to 2D β-Mo2C. The ordered and disordered carbon distributions in 2D α-Mo2C and β-Mo2C, respectively, may be the underlying origin for their different electronic and superconducting properties.

scholarly journals Enhancement of the superconducting transition temperature in FeSe epitaxial thin films by anisotropic compression

2013 ◽  
Vol 103 (17) ◽  
pp. 172602 ◽  
Author(s):  
Fuyuki Nabeshima ◽  
Yoshinori Imai ◽  
Masafumi Hanawa ◽  
Ichiro Tsukada ◽  
Atsutaka Maeda
Keyword(s):  
Thin Films ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Epitaxial Thin Films ◽  
Superconducting Transition

Multilayer E-Beam Deposition and Annealing of Yba2Cu3O7-δ Thin Films on Lagao3 Substrates

1989 ◽  
Vol 169 ◽  
Author(s):  
Richard DeVito ◽  
Brian G. Pazol ◽  
John H. Chaffin ◽  
Roger F. Belt ◽  
Robert Uhrin
Keyword(s):  
Thin Films ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Depth Profiling ◽  
Superconducting Transition ◽  
Transition Width ◽  
Substrate Diffusion ◽  
Annealing Cycle ◽  
Annealing Study ◽  
Beam Deposition

AbstractThin films of YBa2Cu3O7‐δ have been deposited on samples of LaGaO3 substrates by multilayer E‐beam evaporation. Alternating layers of Cu, Y2O3, and BaF2 were deposited on polished (001) substrates. An annealing study was performed to thoroughly blend the layers and minimize substrate interdiffusion. Films were prepared by annealing in wet oxygen at temperatures between 800 °C and 1000 °C. Four point resistance versus temperature curves were obtained to determine the superconducting transition temperature and transition width. Auger depth profiling was performed as a function of annealing cycle to determine the amount of blending of the layers and quantify any substrate diffusion..

scholarly journals Suppression of phase separation and giant enhancement of superconducting transition temperature in FeSe1−xTex thin films

2015 ◽  
Vol 112 (7) ◽  
pp. 1937-1940 ◽  
Author(s):  
Yoshinori Imai ◽  
Yuichi Sawada ◽  
Fuyuki Nabeshima ◽  
Atsutaka Maeda
Keyword(s):  
Phase Separation ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Lattice Strain ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Separation Region ◽  
Superconducting Transition ◽  
Key Factors ◽  
Maximum Value

We demonstrate the successful fabrication on CaF2 substrates of FeSe1−xTex films with 0≤x≤1, including the region of 0.1≤x≤0.4, which is well known to be the “phase-separation region,” via pulsed laser deposition that is a thermodynamically nonequilibrium method. In the resulting films, we observe a giant enhancement of the superconducting transition temperature, Tc, in the region of 0.1≤x≤0.4: The maximum value reaches 23 K, which is ∼1.5 times as large as the values reported for bulk samples of FeSe1−xTex. We present a complete phase diagram of FeSe1−xTex films. Surprisingly, a sudden suppression of Tc is observed at 0.1<x<0.2, whereas Tc increases with decreasing x for 0.2≤x<1. Namely, there is a clear difference between superconductivity realized in x=0−0.1 and in x≥0.2. To obtain a film of FeSe1−xTex with high Tc, the controls of the Te content x and the in-plane lattice strain are found to be key factors.

High Pressure Properties of Superconducting Material Palladium

2013 ◽  
Vol 813 ◽  
pp. 327-331
Author(s):  
Wei Min Peng ◽  
Zhong Li Liu ◽  
Hong Zhi Fu
Keyword(s):  
High Pressure ◽  
Perturbation Theory ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Density Functional ◽  
High Pressures ◽  
Ambient Pressure ◽  
Superconducting Transition ◽  
Superconducting Properties ◽  
Density Functional Perturbation Theory

The electronic and the superconducting properties of Pd were studied in the framework of density functional perturbation theory. We explored the superconducting transition temperature for bulk Pd and predicted possible superconductivity at ambient and high pressures. It is found that of Pd is 0.0356 K at ambient pressure and it decreases with pressure.

Degradation Mechanism of the Superconducting Transition Temperature in Nb Thin Films

2015 ◽  
Vol 32 (4) ◽  
pp. 047403
Author(s):  
Xiao-Hui Song ◽  
Yi-Rong Jin ◽  
Zhen-Jun Fan ◽  
Zhen-Yu Mi ◽  
Dian-Lin Zhang
Keyword(s):  
Thin Films ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Degradation Mechanism ◽  
Superconducting Transition
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