Vortex matching effects in Nb thin films due to Ni nanopillars embedded in anodic aluminum oxide substrates

Trezza, M.; Cirillo, C.; Vorobjeva, A I; Outkina, E. A.; Prischepa, S. L.; Attanasio, C.

doi:10.1088/0953-2048/26/3/035001

Cited by 6 publications

(5 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Depending on the mode of electrochemical anodizing, the pore diameter can be varied in a wide range, from nanometers to microns [379]. Using it as a substrate, it is possible to transfer its nanopatterns onto a superconductor film [380], or, by electrochemically depositing magnetic material inside the pores [381], modify the topology of the order parameter of the superconducting film deposited from above [382]. From the point of view of phononic properties, Al 2 O 3 is convenient because its vibrational spectrum extends up to 30 THz, and the main part of the phonon modes is above 6 THz [383], while the Sn phonon cutoff occurs at approximately 4.4 THz [367].…”

Section: Direct Evidence Of Phonon Softening In Nanostructured Superc...mentioning

confidence: 99%

Phonon softening in nanostructured phonon–mediated superconductors (review)

Prischepa

Kushnir

2023

J. Phys.: Condens. Matter

Self Cite

View full text Add to dashboard Cite

Various aspects of phonon spectrum changes in nanostructured phonon-mediated superconductors are considered. It is shown how, with the development of experimental techniques and, accordingly, obtaining new results, the understanding of the influence of the surface and nanoscale on the magnitude of the electron-phonon interaction and the critical temperature Tc changed and deepened. The review is organized as follows. After the Introduction, in the first part we give the quick theoretical background for the description of superconductivity within the framework of various formalisms. In the second part we describe the properties of granular thin films paying attention to the impact of grain sizes and methods of deposition on the Tc value. The role of material parameters is underlined and different aspects of the behavior of granular thin films are discussed. In the third section the impact of external sources of modification of the phonon spectra like noble gases and organic molecules are considered. Problems and progress in this area are discussed. The fourth part is dedicated to the phonon modification and related quantum size effects in nanostructured superconductors. In the fifth part we review the results of direct evidence of phonon softening in nanostructured superconductors and in the sixth section we discuss a possible alternative description of the superconducting properties of nanostructured superconductors related to the concept of metamaterials. In the seventh and eighth parts we review the impact of substrates with lattice mismatched parameters and graphene sheets, respectively, on the modification of the phonon spectrum and enhancement of superconductivity in various superconducting thin films. Finally, in the last ninth section we consider the nonequilibrium superconductivity driven by femtosecond pulses of light, which leads to generation of coherent phonons and to a significant increase in the critical temperature in a number of superconducting materials.

show abstract

Section: Direct Evidence Of Phonon Softening In Nanostructured Superc...mentioning

confidence: 99%

Phonon softening in nanostructured phonon–mediated superconductors (review)

Prischepa

Kushnir

2023

J. Phys.: Condens. Matter

Self Cite

View full text Add to dashboard Cite

show abstract

“…Thus, the currentt study extends the concept in [15,16] to the design and implementation of the bi-stable MEMS optical filter using the transparent nanoporous anodic aluminum oxide (np-AAO) film. The np-AAO film is a promising material and has found many current applications [17][18][19][20][21]. As reported in [15,16], the np-AAO with hexagonally arranged nanopores is exploited to act as a template to implement 1D nanostructured materials including nanopillars, nanowires and nanodot arrays.…”

Section: Introductionmentioning

confidence: 99%

Nanoporous anodic aluminum oxide as a promising material for the electrostatically-controlled thin film interference filter

Luo

Lee

et al. 2015

J. Micromech. Microeng.

View full text Add to dashboard Cite

This study presents the approach to implement the electrostatically-controlled thin film optical filter by using a nanoporous anodic aluminum oxide (np-AAO) layer as the key suspended micro structure. The bi-stable optical filter operates in the visible spectral range. In this work, the presented bi-stable optical filter has averaged reflectivity of 60%, and the central wavelengths are 580 and 690 nm respectively for on and off states. The presented np-AAO layer offers the following merits for the thin film optical filter: (1) material properties of np-AAO film, such as refractive index, elastic modulus and dielectric constant, can be easily changed by a low temperature pore-widening process, (2) in-use stiction of the suspended np-AAO structure can be reduced by the small contact area of nanoporous textures, (3) driving (pull-in) voltage can be reduced due to a large dielectric constant (εAAO is 7.05) and small stiffness of np-AAO film and (4) dielectric charging can be reduced by the np-AAO material; thus the offset voltage is small. The study reports the design, fabrication and experimental results of the bi-stable optical filter to demonstrate the advantages of the presented device. The np-AAO material also has the potential for applications of other electrostatic drive micro devices.

show abstract

“…This task was studied in S/I/F systems (here "I" indicates an insulating layer). In most of the works, the theoretical investigation was performed in the framework of the Ginzburg-Landau (GL) theory [2,[32][33][34][35][36][37][38][39][40][41][42] (except in the case of reference [36], where the possibility of triplet superconductivity induced by the domain walls was considered). One of the most interesting results was the prediction of maxima in the T c as a function of the external homogeneous magnetic field H 0 .…”

Section: Introductionmentioning

confidence: 99%

Superconducting Order Parameter Nucleation and Critical Currents in the Presence of Weak Stray Fields in Superconductor/Insulator/Ferromagnet Hybrids

et al. 2021

View full text Add to dashboard Cite

The stray fields produced by ferromagnetic layers in Superconductor/Insulator/Ferromagnet (S/I/F) heterostructures may strongly influence their superconducting properties. Suitable magnetic configurations can be exploited to manipulate the main parameters of the hybrids. Here, the nucleation of the superconducting phase in an external magnetic field that periodically oscillates along the film width is studied on the base of the numerical solution of the linearized system of Usadel equations. In addition, the effect of the magnetic configuration of the F-layer on the temperature dependence of the critical current density, Jc(T), is investigated in the framework of the Ginzburg–Landau phenomenological theory on the base of the oscillating model of a stray field. By following this approach, the Jc(T) dependence of a Nb/SiO2/PdNi trilayer is reproduced for different magnetic configurations of the PdNi layer.

show abstract

Vortex matching effects in Nb thin films due to Ni nanopillars embedded in anodic aluminum oxide substrates

Cited by 6 publications

References 20 publications

Phonon softening in nanostructured phonon–mediated superconductors (review)

Phonon softening in nanostructured phonon–mediated superconductors (review)

Nanoporous anodic aluminum oxide as a promising material for the electrostatically-controlled thin film interference filter

Superconducting Order Parameter Nucleation and Critical Currents in the Presence of Weak Stray Fields in Superconductor/Insulator/Ferromagnet Hybrids

Contact Info

Product

Resources

About