Superconductivity in Films of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>β</mml:mi></mml:math>Tungsten and Other Transition Metals

Bond, W. L.; Cooper, A. S.; Andres, K.; Hull, G. W.; Geballe, T. H.; Matthias, B. T.

doi:10.1103/physrevlett.15.260

Cited by 88 publications

(28 citation statements)

References 10 publications

(4 reference statements)

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“…For 0 Oe, the J C0 and J C1 are the same. The J C0 is at 2 K under 0 Oe field (The value in β - W film, of which T C is 3.35 K, is about 26). With the temperature and magnetic field increasing, the values of J C decreases.…”

Section: Discussionmentioning

confidence: 99%

Voltage-current properties of superconducting amorphous tungsten nanostrips

Sun

Wang

Zhao

et al. 2013

Sci Rep

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The voltage-current (V-I) characteristics of tungsten (W) strips patterned by focused-ion-beam assisted deposition were studied at different temperatures and various magnetic fields applied perpendicular to the strips. At fields of 1 Tesla (T) and 2 T, a scaling behavior was observed in V-I isotherms, which can be fitted by quasi-three-dimensional (quasi-3D) vortex-glass (VG) to liquid transition theory.

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Section: Discussionmentioning

confidence: 99%

Voltage-current properties of superconducting amorphous tungsten nanostrips

Sun

Wang

Zhao

et al. 2013

Sci Rep

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“…The wires produced are composed of tungsten, carbon, and gallium in varying proportions (in our case, the atomic concentrations are roughly 30% W, 50% C, and 20% Ga). 4 The superconducting critical temperature of the wires produced is T c ∼ 4 K, an order of magnitude higher than the bulk T c of W. 5 This could be due to the inclusion of Ga, which is itself a superconductor with T c = 1 K. The critical magnetic field of the wires is also strikingly high: at 1 K, H c = 7 T. 6 The W wires are 200 nm wide and 100 nm thick. The dependence of the superconducting properties of these wires on the deposition conditions has been investigated in detail in Li et al 7 The superconducting gap as well as the Abrikosov flux lattice have been studied by scanning tunneling microscopy experiments.…”

Section: The Samplesmentioning

confidence: 98%

Geometry-related magnetic interference patterns in longSNSJosephson junctions

et al. 2012

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We have measured the critical current dependence on the magnetic flux of two long SNS junctions differing by the normal wire geometry. The samples are made by a Au wire connected to W contacts, via focused ion beam assisted deposition. We could tune the magnetic pattern from the monotonic Gaussian-like decay of a quasi-one-dimensional (1D) normal wire to the Fraunhofer-like pattern of a square normal wire. We explain the monotonic limit with a semiclassical 1D model, and we fit both field dependencies with numerical simulations of the two-dimensional Usadel equations. Furthermore, we observe both integer and fractional Shapiro steps. The magnetic flux dependence of the integer steps reproduces as expected that of the critical current I c , while fractional steps decay slower with the flux than I c .

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“…Thus the search for higher-T c superconductors was expanded to alloys, compounds and composites. [1][2][3][4][5][6][7][8] In an alloy, the degree of order can be very important in determining the superconducting properties. For high transition-temperature superconductors the stoichiometric composition and the structural order are of great importance in obtaining a maximal T c .…”

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confidence: 99%

Tunability of the superconductivity of tungsten films grown by focused-ion-beam direct writing

Fenton

Wang

et al. 2008

Journal of Applied Physics

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We have grown tungsten-containing films by focused-ion-beam FIB -induced chemical vapor deposition. The films lie close to the metal-insulator transition with an electrical conductivity which changes by less than 5% between room temperature and 7 K. The superconducting transition temperature Tc of the films can be controlled between 5.0 and 6.2 K by varying the ion-beam deposition current. The Tc can be correlated with how far the films are from the metal-insulator transition, showing a nonmonotonic dependence, which is well described by the heuristic model of Osofsky et al. (Phys. Rev. Lett. 87, 197004 (2001)). Our results suggest that FIB direct-writing of W composites might be a potential approach to fabricate mask-free superconducting devices as well as to explore the role of reduced dimensionality on superconductivity.Keywords: Direct-writing, nanoscale structures, superconductivity, tungsten, focused-ionbeam deposition IntroductionThe investigation of enhanced superconductivity has been a major activity in solid-state physics and materials science in the last few decades. There are only 27 elements which, in bulk form, are superconductors at ambient pressure. The highest critical temperature, T c , of an elemental bulk material is that of niobium (T c = 9.3 K). Thus the search for higher-T c superconductors was expanded to alloys, compounds and composites. [1][2][3][4][5][6][7][8] In an alloy, the degree of order can be very important in determining the superconducting properties. For high transition-temperature superconductors the stoichiometric composition and the structural order are of great importance in obtaining a maximal T c . By contrast, highly disordered transition metals mostly display a higher T c than their annealed ordered counterparts. Tungsten is the superconductor of choice for fabrication of transition-edge sensors (TESs) for optical and near-infared wavelengths due to the tunability of its superconducting transition temperature in the range 100 mK and its relatively weak electron-phonon coupling at such temperatures.[9] Single-crystal tungsten has a very low transition temperature: T c of alpha (bcc) W is 15 mK and that of beta (A15) W is in the range 1 K to 4 K. Amorphous tungsten films [4][5] and alloys, [6][7][8] when rendered into a disordered or granular state, have a T c which can be up to two orders of magnitude larger than that of single-crystal bcc W.Recently the use of a focused ion-or electron-beam to induce the deposition of composite materials from metal-organic precursors has emerged as an important nanofabrication technique. [10][11][12][13][14][15][16][17][18] Such techniques enable the formation of metallic

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Superconductivity in Films ofβTungsten and Other Transition Metals

Cited by 88 publications

References 10 publications

Voltage-current properties of superconducting amorphous tungsten nanostrips

Voltage-current properties of superconducting amorphous tungsten nanostrips

Geometry-related magnetic interference patterns in longSNSJosephson junctions

Tunability of the superconductivity of tungsten films grown by focused-ion-beam direct writing

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