Point-Contact Spectroscopy of Superconducting RNi2B2C (R=Rare Earth, Y)

Yanson, I. K.

doi:10.1007/978-94-011-4834-4_24

Cited by 9 publications

(10 citation statements)

References 35 publications

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“…It fits well with the other RNi 2 B 2 C superconductors with 2∆ 0 /k B T c = 3.63 ± 0.05 ( Fig.13; see Ref. [12]). This is quite surprising, taking into account that among these compounds, there is a nonmagnetic one (Y-compound) and crystals with quite different magnetic order (Er- [20,21], Ho- [5,6], Dy-compounds [22]).…”

Section: Discussionsupporting

confidence: 82%

“…As is well known, PCS spectra of quasiparticle DOS utilizes the Andreev reflection phenomena at the normal (N)-superconductor (S) boundary inside the N-c-S (c-constriction) point contact. The superconducting transition of DyNi 2 B 2 C is at T c = 6 K, deep inside the antiferromagnetic state which occurs at T N = 10.5 K. We show that the 2∆ 0 /k B T c ratio for DyNi 2 B 2 C has the value of 3.6 stated above for other superconducting RNi 2 B 2 C [12], and the DOS and temperature dependence obeys the BCS law. The upper critical field amounts to approximately 0.9 T for a field aligned nominally within the ab-plane.…”

Section: Introductionsupporting

confidence: 54%

“…This may be the cause of the observed suppression of Andreev reflections, as well as the variety of particular contact characteristics. Interestingly, in ErNi 2 B 2 C, where the magnetic moments order antiferromagnetically along the ab-plane, the preliminary results point to a conventional intensity for the Andreev reflection structure [12]. Surprisingly, there is no pronounced anisotropy of H c2 along and perpendicular to the c-axis, like for example, in URu 2 Si 2 , which may be because only the electrons with moments inside the small (δ c )/ξ 0 ((δ c )-elementary cell distance along caxis) angle are magnetically polarized.…”

Section: Discussionmentioning

confidence: 64%

“…Unfortunately, the tunneling characteristic was not of an excellent quality which forces one to suspect that at the surface, the superconductivity is partially depressed. The point-contact measurements of superconducting energy gaps in Y- [4,11,12], Ho- [2] and Er-compounds [12] give 2∆ 0 /k B T c = 3.63 ± 0.05 if for Ho-, one takes the "lower" T * c = 6 K. To our knowledge, there are no tunneling measurements of the superconducting energy gap in any magnetic nickel-borocarbides. It should be noticed that there is no structure in the tunneling spectrum above the gap voltage in Lu/YNi 2 B 2 C, which would allow one to infer the Cooper-pair-mediation mechanism.…”

Section: Introductionmentioning

confidence: 91%

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Point-contact spectroscopy of superconducting energy gap in DyNi2B2C

Yanson

Bobrov

Tomy

et al. 2000

Physica C: Superconductivity

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The superconducting energy gap in DyNi2B2C has been investigated using a point-contact technique based on the Andreev reflection from a normal (N)-superconductor (S) boundary, where N is Ag. The observed differential resistance dV /dI is well described by the Blonder-Tinkham-Klapwijk (BTK) theory based on the BSC density of states with zero broadening parameter. Typically, the intensity of the gap structure amounts to several percentage of the normal state resistance, which is an order of magnitude less than predicted by the theory. For DyNi2B2C with Tc < TN (the Neel temperature), we found gap values satisfying the ratio of 2∆0/kBTc = 3.63 ± 0.05 similar to other superconducting nickel-borocarbides, both nonmagnetic and magnetic with Tc ≥ TN . The superconducting gap nonlinearity is superimposed on the antiferromagnetic structure in dV /dI(V ) which is suppressed at the magnetic field of the order of 3T applied nominally in the ab-plane and temperature ≥ 11 K. The observed superconducting properties depend on the exact composition and structure at the surface of the crystal.

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Section: Discussionsupporting

confidence: 82%

Section: Introductionsupporting

confidence: 54%

Section: Discussionmentioning

confidence: 64%

Section: Introductionmentioning

confidence: 91%

See 2 more Smart Citations

Point-contact spectroscopy of superconducting energy gap in DyNi2B2C

Yanson

Bobrov

Tomy

et al. 2000

Physica C: Superconductivity

View full text Add to dashboard Cite

show abstract

“…Andreev-reflection point contact spectroscopy is based on the measurements of the transformation of the quasiparticles to Cooper pairs, which happens at least at the distance of coherence length ξ from the interface between a normal metal N and superconductor S. 1 Electronic transport in NS boundary is described by the Artemenko,Volkov and Zaitsev, 2 Zaitsev 3 and by the BTK (Blonder-Tinkham-Klapwijk) formalism, 4 which was developed for the ballistic junctions. In this regime a point contact consists of the normal metal N and superconductor S, whose radius r 0 is significantly less than the mean free path l. The ratio of conductance inside and outside the gap voltage predicted by the BTK is a factor of 2.…”

Section: Introductionmentioning

confidence: 99%