Boron isotope effect in Ni and Pd based borocarbide superconductors

Lawrie, D. D.; Franck, J. P.

doi:10.1016/0921-4534(95)00088-7

Cited by 59 publications

(29 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To summarize we have measured the Carbon isotope effect in but similar to that reported for Rb 3 C 60 α C =0.37 [22], 0.21 [23], and substantially higher than that for the related borocarbide YNi 2 B 2 C, where α C is reported to be very close to zero (α C =0.07) [24]. For the borocarbide, however, the Boron isotope effect is measured to be α B =0.25 [24] and 0.21 [25] indicating a substantial contribution of boron derived phonons to the superconducting mechanism.…”

supporting

confidence: 49%

See 1 more Smart Citation

Carbon isotope effect in superconductingMgCNi3

Klimczuk

Cava

2004

Phys. Rev. B

View full text Add to dashboard Cite

The effect of Carbon isotope substitution on Tc in the intermetallic perovskite superconductor MgCNi 3 is reported. Four independent groups of samples were synthesized and characterized. The average Tc for the 12 C samples was found to be 7.12±0.02 K and the average Tc for the 13 C samples was found to be 6.82±0.02 K. The resulting carbon isotope effect coefficient is α C = 0.54±0.03. This indicates that carbon-based phonons play a critical role in the presence of superconductivity in this compound.PACS numbers: 74.70Ad, 74.62BfMgCNi 3 has a non-oxygen based perovskite structure and is superconducting near 7K [1]. MgCNi 3 and the layered borocarbides (RENi 2 B 2 C) [2] form a family of Ni-rich intermetallic superconductors in which the Ni d states are found at the Fermi level (E F ), and therefore the appearance of superconductivity rather then magnetism is at first unexpected. Considering their structures and the potential magnetism, MgCNi 3 and the borocarbides appear to be a bridge between conventional, intermetallic superconductors and high-T C cuprates, and thus questions about the nature of their superconductivity are of interest.For the case of MgCNi 3 , conventional phononmediated, moderate [1,3] and strong [4,5]

show abstract

supporting

confidence: 49%

“…For the borocarbide, however, the Boron isotope effect is measured to be α B =0.25 [24] and 0.21 [25] indicating a substantial contribution of boron derived phonons to the superconducting mechanism. The boron isotope effect value in the borocarbide is very close to that in MgB 2 , reported to be in the range α B =0.28 [26] to α B =0.30 [27].…”

mentioning

confidence: 99%

Carbon isotope effect in superconductingMgCNi3

Klimczuk

Cava

2004

Phys. Rev. B

View full text Add to dashboard Cite

show abstract

“…The T c values as defined by ρ = 0, onset of diamagnetism in M(T ) measurements and mid-point of the heat capacity rise (or by balancing of the normal state and superconducting state entropies) are ∼ 15.9 K and ∼ 15.1 K for samples A and B respectively. This difference in T c between samples A and B is partially due to the boron isotope effect [16,17] and partially due to different scattering in two samples as can be see from the difference in the residual resistivity ratio, RRR = ρ(300K)/ρ(17K) ≈ 63 and 16 for A and B respectively [13] . It should be noted that sample B had a small, rather broad, bump in resistivity near 30 K, feature that was not observed in the sample A or other flux-grown YNi 2 B 2 C samples.…”

Section: Thermal Expansionmentioning

confidence: 98%

Anisotropic thermal expansion and magnetostriction of YNi₂B₂C single crystals

Bud’ko

Schmiedeshoff

Lapertot

et al. 2006

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

Abstract. We present results of anisotropic thermal expansion and low temperature magnetostriction measurements on YNi 2 B 2 C single crystals grown by high temperature flux and floating zone techniques. Quantum oscillations of magnetostriction were observed at low temperatures for H c starting at fields significantly below H c2 (H < 0.7H c2 ). Large irreversible, longitudinal magnetostriction was seen in both, inplane and along the c-axis, directions of the applied magnetic field in the intermediate superconducting state. Anisotropic uniaxial pressure dependencies of T c were evaluated using results of zero field, thermal expansion measurements.

show abstract

“…The mechanism of Cooper pairing in these compounds is not known in detail although they are commonly believed to be mediated by the ordinary electron-phonon interaction, like A15. The boron isotope effect [2,3] clearly points that the phonons are involved in superconductivity . Whether these compounds are s− or d−wave superconductors [4] is still under debate.…”

Section: Introductionmentioning

confidence: 99%