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Wyszukujesz frazę "74.78.-w" wg kryterium: Temat


Tytuł:
DC nanoSQUID from Nb thin films
Autorzy:
Štrbík, V.
Pisarčík, M.
Gaži, Š.
Španková, M.
Powiązania:
https://bibliotekanauki.pl/articles/1054826.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.78.-w
74.70.Ad
85.25.Dq
Opis:
We have prepared Nb thin film (thickness 80-100 nm) nanoSQUID with two symmetrically placed nanosized constrictions in superconducting loop. The nanoSQUID was prepared in two steps: at first a microsized SQUID was prepared and in the second step nanosized constrictions of the width of 120 nm in the SQUID loop were created by a focused ion beam technique. We studied the electrical and magnetic properties. From the obtained results, SQUID and constriction dimensions, the spin sensitivity was estimated to be about 50 μ_{B} Hz^{-1/2}. Further improvement of spin sensitivity is possible by lowering the SQUID and constriction dimensions.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 1054-1056
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design and Analysis of a Microstrip Antenna Based on Superconducting Material for Millimeter Wave Applications
Autorzy:
Djidel, S.
Bouamar, M.
Khedrouche, D.
Powiązania:
https://bibliotekanauki.pl/articles/1032556.pdf
Data publikacji:
2017-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.78.-w
74.72.-h
84.40.Ba
84.40.Ua
84.40.Gf
Opis:
In this paper, we present a design and analysis of microstrip antenna based on superconducting material for millimeter wave applications. The proposed antenna is simulated using electromagnetic microwave studio computer simulator CST. The structure is made by two materials: the yttrium barium copper oxide (YBCO) thin film superconductor material as the patch and silicon Si as substrate with permittivity of 11.9. The superconductor material is characterized by a conductivity of 1.62×10⁷ S/m and critical high temperature of 89 K. The simulated results concerning the return loss show that our structure has ultra wide band over 27 to 70 GHz. Low return loss of the superconductor antenna compared with his perfect conductor counterpart is achieved. In addition, good radiation pattern characteristics are obtained in the frequency band of operation. The proposed antenna has also overall size of 3×3 mm², which facilitate its integration in architecture of communications systems.
Źródło:
Acta Physica Polonica A; 2017, 131, 1; 109-111
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetoresistance study of c-axis oriented YBCO thin film
Autorzy:
Chrobak, M.
Woch, W.
Kowalik, M.
Zalecki, R.
Giebułtowski, M.
Przewoźnik, J.
Kapusta, Cz.
Szwachta, G.
Powiązania:
https://bibliotekanauki.pl/articles/1054863.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.72.-h
74.78.-w
74.25.Op
74.25.Qt
74.78.Bz
Opis:
The c-axis orientation YBa₂Cu₃O_δ thin film was prepared directly on MgO substrate by the pulse laser deposition. The thickness of the film is 170 nm. The superconducting critical temperature is T_{c50%}=87.5 K and the width of superconducting transition is ΔT = 1.8 K. The temperature dependences of magnetoresistance were measured up to 90 kOe. The widths of the transition to the superconducting state versus applied magnetic field were derived and they were fitted using the formula: Δ T=CH^m +Δ T₀. The irreversibility fields as a function of temperature were obtained and fitted by the de Almeida and Thouless-like equation: H_{irr}=H_{irr0}(1-T/T_{c0})^n. The irreversibility field at the liquid nitrogen temperature was calculated and it is H_{irr}=43.8 kOe when the applied magnetic field is parallel to the c-axis.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 1018-1020
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Time-Reversal Invariant Topological Superconductivity in Quasi-One-Dimensional Structures
Autorzy:
Mammadova, S.
Nakhmedov, E.
Alekperov, O.
Powiązania:
https://bibliotekanauki.pl/articles/1398788.pdf
Data publikacji:
2016-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.78.-w
71.10.Pm
71.70.Ej
74.50.+r
Opis:
It is shown that a time-reversal invariant topological superconductivity can be realized in a quasi-one-dimensional structure, which is fabricated by filling the superconducting materials into the periodic channel of dielectric matrices like zeolite and asbestos under high pressure. The topological superconducting phase sets up in the presence of large spin-orbit interactions when s-wave intra-wire and d-wave inter-wire pairings take place. Kramers pairs of Majorana bound states emerge at the edges of each wire. The time-reversal topological superconductor belongs to DIII class of symmetry with a Z₂ invariant.
Źródło:
Acta Physica Polonica A; 2016, 129, 4; 800-802
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Josephson Junctions Like Behavior in Superconducting Nb Films with Diluted Triangular Arrays of Antidots
Autorzy:
Mumtaz, M.
He, S.
Qiu, X.
Kamran, M.
Powiązania:
https://bibliotekanauki.pl/articles/1192515.pdf
Data publikacji:
2015-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.25.F-
74.78.-w
74.81.Fa
Opis:
We present current versus voltage (I-V) measurement on superconducting Nb films with diluted triangular arrays (honeycomb and kagome) of antidots. Peaks and dips appearing in the derivative (dV/dI) of I-V curves showing the variation in the resistance is the indication of Josephson Junctions like weak-links in these systems. These observations also reveal the presence of mobile interstitial vortices in these lattices with regular pinning arrays. This behavior is predominant in honeycomb arrays due to large density of interstitial spaces in this system as compared that of to kagome lattice. This behavior can be tuned by temperature as well as external magnetic field but the tuning values of these parameters can be different for different symmetries of antidots.
Źródło:
Acta Physica Polonica A; 2015, 127, 4; 898-900
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal Fluctuations of Bismuth Based 1G Tape
Autorzy:
Chrobak, M.
Woch, W.
Zalecki, R.
Kołodziejczyk, A.
Powiązania:
https://bibliotekanauki.pl/articles/1385435.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.72.-h
74.78.-w
74.40.-n
74.62.-c
Opis:
The thermal fluctuations of bismuth based commercial 1G tape were studied near the critical temperature $T_{c}$=110.2 K. The detailed analysis of the temperature dependence of resistivity measurements was made in the temperature region from the zero resistance critical temperature up to 300 K. The thermal fluctuations of conductivity were analysed using the Aslamazov-Larkin microscopic approach and the critical exponents were calculated close to the transition temperature.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 306-308
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of Superconductor/Photosemiconductor Contact Structures in Electronics
Autorzy:
Bunda, V.
Bunda, S.
Komanicky, V.
Botko, M.
Čižmár, E.
Feher, A.
Powiązania:
https://bibliotekanauki.pl/articles/1202071.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.45.+c
74.78.-w
85.25.Hv
Opis:
In recent years, two-dimensional (2D) nanostructured materials, such as nanoplates and nanosheets, have attracted much attention because of their unique electronic, magnetic, optical, and catalytic properties, which mainly arise from their large surface areas, nearly perfect crystallinity, structural anisotropy, and quantum confinement effects in the thickness. The 2D nanostructured materials can be used as building blocks for advanced materials and devices with designed functions in areas as diverse, as lasers, transistors, catalysis, solar cells, light emission diodes, chemical and biological sensors. We report physical properties of YBCO/BiOI contact structures and electrophysical properties of BiOI single crystal.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 362-363
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enhancement of the Critical Temperature Induced by the Quantum Size Effect in Superconducting Nanofilms
Autorzy:
Wójcik, P.
Powiązania:
https://bibliotekanauki.pl/articles/1374149.pdf
Data publikacji:
2014-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.78.-w
73.61.-r
74.78.Na
Opis:
The interplay between the quantum size effect and superconductivity in the metallic Al nanofilms has been studied with the use of the self-consistent numerical solutions of the Bogoliubov-de Gennes equations. We have shown that the critical temperature of the metallic nanofilm oscillates as a function of the nanofilm thickness. This phenomenon results from the quasi-particle energy quantization induced by the confinement of electrons in the direction perpendicular to the film. For the ultrathin nanofilms with thickness 1-2 nm we have found that the critical temperature increases up to value several times higher as compared to the one measured in the bulk.
Źródło:
Acta Physica Polonica A; 2014, 126, 4a; A-130-A-132
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Growth and Characterization of $YBa_2Cu_3O_{7-δ}$ Films Deposited by Laser Ablation on $CeO_2$-Buffered Sapphire
Autorzy:
Abal'osheva, I.
Zaytseva, I.
Aleszkiewicz, M.
Malinowski, A.
Bezusyy, V.
Syryanyy, Y.
Gierłowski, P.
Abal'oshev, O.
Kończykowski, M.
Cieplak, M.
Powiązania:
https://bibliotekanauki.pl/articles/1374756.pdf
Data publikacji:
2014-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.78.-w
77.55.Px
81.15.Fg
Opis:
In this work we study the growth, by pulsed laser deposition, of $YBa_2Cu_3O_{7-δ}$ (YBCO) films on the $CeO_2$-buffered R-cut sapphire substrates, with the buffer layer recrystallized prior to the deposition of superconductor. We find that the superconducting critical temperature and the critical current density of the films are very close to similar parameters for the YBCO films grown on lattice-matched single crystalline substrates. It appears that the structural defects in the buffer layer affect the microstructure of YBCO films, resulting in high values of the critical current density, suitable for applications.
Źródło:
Acta Physica Polonica A; 2014, 126, 4a; A-69-A-72
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase Diagram and Activation Energy for Vortex Pinning in Nb/(Co,Pd) Superconductor-Ferromagnet Bilayer
Autorzy:
Syryanyy, Y.
Aleszkiewicz, M.
Cieplak, Marta
Zhu, L.
Chien, C.
Powiązania:
https://bibliotekanauki.pl/articles/1374109.pdf
Data publikacji:
2014-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.25.F-
74.25.N-
74.25.Wx
74.62.-c
74.70.-b
74.78.-w
74.78.Fk
75.70.Kw
75.70.-i
Opis:
Using the magnetoresistance measurements we study the phase transition line and the activation energy for vortex pinning in superconductor/ferromagnet bilayer, built of a ferromagnetic Co/Pd multilayer with perpendicular magnetic anisotropy, and a niobium film, with insulating layer in-between to eliminate proximity effect. The domain width is reversibly pre-defined using the angle-dependent demagnetization. We find that the enhancement of the activation energy for vortex pinning by magnetic domains is rather modest, by a factor of about 2.1. We attribute this to large domain width, and large dispersion of the domain width in this bilayer.
Źródło:
Acta Physica Polonica A; 2014, 126, 4a; A-123-A-126
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of Niobium Thin Films under Pressure
Autorzy:
Pristáš, G.
Gabáni, S.
Orendáč, M.
Komanický, V.
Gažo, E.
Powiązania:
https://bibliotekanauki.pl/articles/1371538.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.78.-w
81.40.Vw
74.62.Fj
Opis:
Niobium is widely used in many important superconducting applications. At ambient pressure, bulk Nb has the highest critical temperature, $T_c$ ≈ 9.25 K among the superconducting elements. Thin films of Nb show several differences in behavior in comparison with bulk Nb, e.g. substantial increase in the upper critical field ($H_{C2}$). Critical temperature of superconducting transition is usually lower for thin films than in bulk sample and depends on thickness of the film, size of grains etc. We prepared 100 nm thick niobium thin films in the high vacuum DC magnetron sputtering system, with $T_c$=8.95 K at ambient pressure. In this study, we performed measurements of superconducting transition temperature by electrical resistivity measurements of Nb thin film under hydrostatic pressure of up to 30 kbar. We observed an increase of $T_c$ with increasing value of pressure ($dT_c$/dp=7.3 mK/kbar). On the other side in the case of bulk sample of Nb we observed a decrease of $T_c$ value ($dT_c$/dp=-2.5 mK/kbar) with increasing applied pressure. Difference in superconducting properties between niobium bulk and thin film under pressure is discussed.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 346-347
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Superconductivity Near Transition to Insulating State in MoC Ultrathin Films Studied by Subkelvin STM
Autorzy:
Szabó, P.
Neilinger, P.
Trgala, M.
Grajcar, M.
Samuely, P.
Powiązania:
https://bibliotekanauki.pl/articles/1372334.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.50.+r
74.78.-w
74.81.-g
Opis:
We study the homogeneously disordered MoC thin films with thicknesses of 10 and 5 nm and the superconducting transition temperatures near 6 and 4 K, significantly decreased as compared to the bulk $T_{c}$=8.32 K due to a disorder. The scanning tunnelling spectroscopy reveals in the thicker sample a BCS superconducting energy gap Δ with a broadening parameter Γ equal to about 10 per cent of Δ. Remarkably, Γ increases with temperature. The thinner, more disordered sample shows a gapped superconducting density of states but without any coherence peaks at the gap edge, which could not be approximated by the BCS DOS. Moreover, the reduced DOS around the Fermi level persists above the resistive transition temperature reminding the pseudo-gap known from high-$T_{c}$ cuprates.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 368-369
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal Fluctuations in YBCO Thin Film on MgO Substrate
Autorzy:
Chrobak, M.
Woch, W.
Szwachta, G.
Zalecki, R.
Gondek, Ł.
Kołodziejczyk, A.
Kusiński, J.
Powiązania:
https://bibliotekanauki.pl/articles/1374789.pdf
Data publikacji:
2014-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.72.-h
74.78.-w
74.40.-n
74.62.-c
Opis:
The c-axis orientation $YBa_2Cu_3O_δ$ thin film was prepared directly on MgO substrate by the pulse laser deposition. The thickness of the film was 170 nm. The superconducting critical temperature was $T_{c50%}$=89 K and the width of superconducting transition was Δ T= 1.6 K. Temperature dependence of the critical current of the film was obtained from the temperature dependences of the imaginary part of the AC susceptibility using the Bean model. The critical current density was $J_{c}$=1.2×$10^7$ A/$cm^{2}$ at 77 K in the self field. The critical exponents were calculated for several values of the DC applied magnetic field using the temperature dependences of magnetoresistivity. The thermal fluctuations in vicinity of the critical temperature were analysed.
Źródło:
Acta Physica Polonica A; 2014, 126, 4a; A-88-A-91
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ultrathin Niobium in the Si/Nb/Si Trilayers
Autorzy:
Zaytseva, I.
Abal'oshev, O.
Dłużewski, P.
Minikayev, R.
Cieplak, Marta
Zhu, L.
Chien, C.
Powiązania:
https://bibliotekanauki.pl/articles/1374193.pdf
Data publikacji:
2014-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.78.-w
74.70.Ad
74.25.-q
Opis:
We study magnetotransport properties of the Si/Nb/Si trilayers, in which the thickness of niobium, d, changes from 1.1 nm to 50 nm, while the thickness of Si is fixed at 10 nm. The niobium films are amorphous for d < 4 nm, while in thicker films the alligned polycrystalline grains are formed. We observe that the Hall coefficient changes sign into negative in the films with d < 1.6 nm. We also find that in the ultrathin films the magnetic field induces a transition from the superconducting into a metallic phase with the resistance smaller than the normal-state resistance.
Źródło:
Acta Physica Polonica A; 2014, 126, 4a; A-140-A-144
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
XPS Study of Superconducting $LiTi_2O_4$ and $LiTi_{2-x}Cu_{x}O_4$ Sol-Gel Derived Powders and Thin Films
Autorzy:
Łapinski, M.
Kościelska, B.
Winiarski, A.
Sadowski, W.
Powiązania:
https://bibliotekanauki.pl/articles/1374065.pdf
Data publikacji:
2014-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.78.-w
81.20.Fw
Opis:
In this work X-ray photoelectron studies of lithium titanate and copper doped lithium titanate are presented. Both, powder and thin films samples were prepared by sol-gel method. After preparation, the samples were heated in argon atmosphere at various temperatures in a range from 500 °C to 600 °C for 20 h. The crystalline structure of the samples was investigated by X-ray diffraction, while the oxidation states of the elements were examined by X-ray photoelectron spectroscopy method. X-ray diffraction measurements confirmed spinel phase of all manufactured samples. However it is well known that electrical and superconducting properties of lithium titanate are strongly correlated not only with structure, but also with oxidation state of Ti ions. X-ray photoelectron spectroscopy investigations revealed mixture of $Ti^{3+}$ and $Ti^{4+}$ ions, although the $Ti^{3+}$/$Ti^{4+}$ ratio is much smaller than $1/2$ needed for superconductivity. In this work dependence between calcination temperature as well as amount of Cu dopant and $Ti^{3+}$/$Ti^{4+}$ proportion are reported.
Źródło:
Acta Physica Polonica A; 2014, 126, 4a; A-107-A-110
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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