Upper critical field of niobium nitride thin films

Vasyutin, M. A.; Kuz’michev, N. D.; Shilkin, D. A.

doi:10.1134/s1063783416020311

Cited by 7 publications

(2 citation statements)

References 18 publications

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“…From the upper critical fields measured for film grown at optimal conditions (Fig. 4), the extrapolated perpendicular critical field was determined to be H c2 (0) = 319 kOe and the estimated coherence length is ξ(0) = 3.2 nm, slightly smaller than the bulk value of 5 nm reported in literature [27,28]. This reduced value of ξ(0) is the result of the renormalization of coherence length due to short electron mean-free path in disordered sputtered films.…”

Section: A Characterization Of Thick Nbn Filmsmentioning

confidence: 77%

Room temperature deposition of superconducting niobium nitride films by ion beam assisted sputtering

et al. 2018

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We use room temperature ion beam assisted sputtering (IBAS) to deposit niobium nitride thin films. Electrical and structural characterizations were performed by electric transport and magnetization measurements at variable temperatures, X-ray diffraction and atomic force microscopy. Compared to reactive sputtering of NbN, films sputtered in presence of an ion beam show remarkable increase in the superconducting critical temperature Tc, while exhibiting lower sensitivity to nitrogen concentration during deposition. Thickness dependence of the superconducting critical temperature is comparable to films prepared by conventional methods at high substrate temperatures and is consistent with behavior driven by quantum size effects or weak localization. arXiv:1803.02417v3 [cond-mat.supr-con]

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Section: A Characterization Of Thick Nbn Filmsmentioning

confidence: 77%

Room temperature deposition of superconducting niobium nitride films by ion beam assisted sputtering

et al. 2018

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“…Superconducting NbN material is of considerable interest for various kinds of applications. The upper critical field of this material can exceed 50 T and the transition temperature T c is above 15 K. [1][2][3] Over the past fifteen years, meander nanowires made from ultra-thin films show great potential for single photon detections. [4][5][6] The devices are normally current biased and operate in the region very close to superconductingresistive transition.…”

Section: Introductionmentioning

confidence: 99%

Investigation of dimensionality in superconducting NbN thin film samples with different thicknesses and NbTiN meander nanowire samples by measuring the upper critical field*

et al. 2020

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We study superconducting properties of NbN thin film samples with different thicknesses and an ultra-thin NbTiN meander nanowire sample. For the ultra-thin samples, we found that the temperature dependence of upper critical field (H c2) in parallel to surface orientation shows bending curvature close to critical temperature T c, suggesting a two-dimensional (2D) nature of the samples. The 2D behavior is further supported by the angular dependence measurements of H c2 for the thinnest samples. The temperature dependence of parallel upper critical field for the thick films could be described by a model based on the anisotropic Ginzburg–Landau theory. Interestingly, the results measured in the field perpendicular to the film surface orientation show a similar bending curvature but in a much narrow temperature region close to T c for the ultra-thin samples. We suggest that this feature could be due to suppression of pair-breaking caused by local in-homogeneity. We further propose the temperature dependence of perpendicular H c2 as a measure of uniformity of superconducting ultra-thin films. For the thick samples, we find that H c2 shows maxima for both parallel and perpendicular orientations. The H c2 peak for the perpendicular orientation is believed to be due to the columnar structure formed during the growth of the thick films. The presence of columnar structure is confirmed by transmission electron microscopy (TEM). In addition, we have measured the angular dependence of magneto-resistance, and the results are consistent with the H c2 data.

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Specificities of Current–Voltage Characteristics of NbN Superconducting Films in a Magnetic Field

Vasyutin

Kuz’michev

Shilkin

2020

Phys. Metals Metallogr.

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Upper critical field of niobium nitride thin films

Cited by 7 publications

References 18 publications

Room temperature deposition of superconducting niobium nitride films by ion beam assisted sputtering

Room temperature deposition of superconducting niobium nitride films by ion beam assisted sputtering

Investigation of dimensionality in superconducting NbN thin film samples with different thicknesses and NbTiN meander nanowire samples by measuring the upper critical field*

Specificities of Current–Voltage Characteristics of NbN Superconducting Films in a Magnetic Field

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