Experimental observation of thermal fluctuations in single superconducting Pb nanoparticles through tunneling measurements

Brihuega, I.; García-García, Antonio M.; Ribeiro, Pedro; Ugeda, Miguel M.; Michaelis, Christian H.; Bose, Sangita; Kern, Klaus

doi:10.1103/physrevb.84.104525

Cited by 42 publications

(42 citation statements)

References 41 publications

(81 reference statements)

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“…is the gap energy) [4], while phonon softening is the possible reason for the increasing T c as well as Δ(0)/T c in the weak coupling Type 1 superconductors, agreement with the Anderson criterion [5].…”

Section: Introductionsupporting

confidence: 76%

Synthesis of Ultrafine High- <inline-formula> <tex-math notation="LaTeX">$T_{C}$</tex-math></inline-formula> Superconducting <inline-formula> <tex-math notation="LaTeX">$\mbox{GdBa}_2\mbox{Cu}_3\mbox{O}_{7\mbox{-}{x}}$</tex-math></inline-formula> Powder

Kargar

Alikhanzadeh-Arani

Salavati‐Niasari

2015

IEEE Trans. Appl. Supercond.

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GdBa 2 Cu 3 O 7-X (Gd123) nanowires were synthesized using a modified sol-gel method, in the presence of an excellent surfactant, benzene tricarboxylic acid. The obtained results revealed that the decomposition of BaCO 3 and subsequent formation of the pure Gd123 phase complete after re-calcination process at 900 ºC. Structural study using Rietveld refinement of XRD and also electron diffraction patterns indicated an orthorhombic structure with Pmmm space group. It can be deduced that the shape and particle size of the products are greatly affected by the concentration of the surfactant. Magnetic susceptibility measurements showed clear diamagnetic behavior below the critical temperature of about 91.78 K in the nanowires, which is comparable to that in the bulk ones. Temperature dependence of the magnetic susceptibility was also found to be approximately insensitive to the strength of the applied magnetic field.Phase identification was carried out for the as-precipitated and heat treated samples by an X-ray diffraction (XRD) method with a Rigaku D-max C III, X-ray diffractometer using Ni-filtered Cu K α radiation. Scanning electron microscopy (SEM) images were obtained on Philips XL-30ESEM equipped with an energy dispersive X-ray spectroscopy. The compositional analysis was done by energy dispersive X-ray (EDS, Kevex, Delta Class I). The morphology of the as-precipitated and heat treated samples was observed with a transmission electron microscope (TEM) of Philips EM208 transmission electron microscope with an accelerating voltage of 200 kV. Fourier transform infrared (FT-IR) spectra were recorded on Shimadzu Varian 4300 spectrophotometer in KBr pellets. Synthesis of Gd123 nanoparticlesAll the chemical reagents used in our experiments were of analytical grade, purchased from Aldrich Co. (with purify over 99%), and were used as received without further purification. A homogenous and light-blue solution with overall cation stoichiometry of Gd:Ba:Cu = 1:2:3 was obtained by dissolving the metal nitrates in polypropylene glycol. Polypropylene glycol (PPG) can play the role of a surfactant in the solution, too. 13/3 mmol benzene tricarboxylic acid (BTCA), in the mole ratio BTCA:Y= 13/3:1, was dissolved in 50 ml polypropylene glycol, and then the Gd123 solution was slowly added to that under vigorous stirring. The resulted light-blue viscous fluid was heated in the furnace at 300°C for about 1 h and cooled to room temperature. Finally, the obtained powder was calcined with a heating rate of 5 C/min up to 900˚C for 8 h, and then slowly cooled down to room temperature with a cooling rate of 2 C/min and crushed to a fine powder. Samples were re-calcined under the same conditions as the first calcination. The superconductivity phase formation process was completed with annealing treatment to 700˚C with a rate of 2˚C/min for 3 h and then cooling at the same conditions to room temperature. The optimum partial pressure was 0.5 bar during the entire thermal decomposition process 1051-8223 (c)

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Section: Introductionsupporting

confidence: 76%

Synthesis of Ultrafine High- <inline-formula> <tex-math notation="LaTeX">$T_{C}$</tex-math></inline-formula> Superconducting <inline-formula> <tex-math notation="LaTeX">$\mbox{GdBa}_2\mbox{Cu}_3\mbox{O}_{7\mbox{-}{x}}$</tex-math></inline-formula> Powder

Kargar

Alikhanzadeh-Arani

Salavati‐Niasari

2015

IEEE Trans. Appl. Supercond.

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“…Within the past years, the observation of novel phenomena related to finite size effects on surfaces, ultra-thin films and nanoparticles involving elementary superconductors (SCs) excite intense scientific interest, e.g. the parity effect in SC [1] or the shell effect of SC nanoparticles [2,3]. Local probe techniques are indispensable tools to investigate these effects on the atomic scale.…”

Section: Introductionmentioning

confidence: 99%

STM study of the preparation of clean Ta(110) and the subsequent growth of two-dimensional Fe islands

2016

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This report deals with the preparation of a clean Ta(110) surface, investigated by means of scanning tunneling microscopy/spectroscopy as well as by low-energy electron diffraction and Auger electron spectroscopy. The surface initially exhibits a surface reconstruction induced by oxygen contamination. This reconstruction can be removed by annealing at high temperatures under ultrahigh vacuum conditions. The reconstruction-free surface reveals a surface resonance at a bias voltage of about -500 mV. The stages of the transformation are presented and discussed. In a next step, Fe islands were grown on top of Ta(110) and investigated subsequently. An intermixing regime was identified for annealing temperatures of (550 -590) K.

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“…Besides other possibilities such as a small variation in the differential conductivity of the tip, this tail could originate from fluctuation effects. [33] By systematically recording dI/dV spectra between 0 T and 9 T we can directly observe at which magnetic field the superconducting gap vanishes. To determine a quantitative value for the critical field, B c , we extract the width of the superconducting gap of each spectrum and fit its evolution with magnetic field with the functional form expected for the superconducting order parameter.…”

Section: Resultsmentioning

confidence: 99%

Closing the superconducting gap in small Pb nanoislands with high magnetic fields

et al. 2016

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Superconducting properties change in confined geometries. Here we study the effects of strong confinement in nanosized Pb-islands on Si(111) 7×7. Small hexagonal islands with diameters less than 50 nm and a uniform height of 7 atomic layers are formed by depositing Pb at low temperature and annealing at 300 K. We measure the tunneling spectra of individual Pb-nanoislands using a low-temperature scanning tunneling microscope operated at 0.6 K, and follow the narrowing of the superconducting gap as a function of magnetic field. We find the critical magnetic field, at which the superconducting gap vanishes, reaches several Tesla, which represents a greater than 50-fold enhancement compared to the bulk value. By independently measuring the size of the superconducting gap, and the critical magnetic field that quenches superconductivity for a range of nanoislands we can correlate these two fundamental parameters and estimate the maximal achievable critical field for 7 ML Pb-nanoislands to 7 T.

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Experimental observation of thermal fluctuations in single superconducting Pb nanoparticles through tunneling measurements

Cited by 42 publications

References 41 publications

Synthesis of Ultrafine High- <inline-formula> <tex-math notation="LaTeX">$T_{C}$</tex-math></inline-formula> Superconducting <inline-formula> <tex-math notation="LaTeX">$\mbox{GdBa}_2\mbox{Cu}_3\mbox{O}_{7\mbox{-}{x}}$</tex-math></inline-formula> Powder

Synthesis of Ultrafine High- <inline-formula> <tex-math notation="LaTeX">$T_{C}$</tex-math></inline-formula> Superconducting <inline-formula> <tex-math notation="LaTeX">$\mbox{GdBa}_2\mbox{Cu}_3\mbox{O}_{7\mbox{-}{x}}$</tex-math></inline-formula> Powder

STM study of the preparation of clean Ta(110) and the subsequent growth of two-dimensional Fe islands

Closing the superconducting gap in small Pb nanoislands with high magnetic fields

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