Superconducting alloys with paramagnetic impurities I: Theory of the upper critical field

Schachinger, E.

doi:10.1016/0921-4534(89)90100-7

Cited by 9 publications

(1 citation statement)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is thought that these local moments form on the nearest neighbour Cu atoms rather than on the Zn site itself. 87 There has been much debate 88,89 as to whether the mechanism for pair breaking in YBCO crystals with Zn impurities is local moment scattering or potential scattering due to the Zn impurity (of course the two mechanisms are not mutually exclusive 90 ). Recent work by Davis et al 40,41 indicates that non-magnetic scattering is the dominant mechanism by which Zn impurities 41 lower T c and further that even the magnetic impurities (Ni) act primarily as potential scatterers.…”

Section: B Non-magnetic Disorder In Other Superconductorsmentioning

confidence: 99%

Dependence of the superconducting transition temperature of organic molecular crystals on intrinsically nonmagnetic disorder: A signature of either unconventional superconductivity or the atypical formation of magnetic moments

Powell

McKenzie

2004

Phys. Rev. B

View full text Add to dashboard Cite

We give a theoretical analysis of published experimental studies of the effects of impurities and disorder on the superconducting transition temperature, Tc, of the organic molecular crystals κ-(BEDT-TTF)2X (where X=Cu[N(CN)2]Br and Cu(NCS)2 and BEDT-TTF is bis(ethylenedithio)tetrathiafulvalene) and β-(BEDT-TTF)2X (for X=I3 and IBr2). The Abrikosov-Gorkov (AG) formula describes the suppression of Tc both by magnetic impurities in singlet superconductors, including s-wave superconductors and by non-magnetic impurities in a non-s-wave superconductor. We show that various sources of disorder (alloying anions, fast electron irradiation, disorder accidentally produced during fabrication and cooling rate induced disorder) lead to the suppression of Tc as described by the AG formula. This is confirmed by the excellent fit to the data, the fact that these materials are in the clean limit and the excellent agreement between the value of the interlayer hopping integral, t ⊥ , calculated from this fit and the value of t ⊥ found from angular-dependant magnetoresistance and quantum oscillation experiments. There are only two scenarios consistent with the current state of experimental knowledge. If the disorder induced by all of the four methods considered in this paper is, as seems most likely, non-magnetic then the pairing state cannot be s-wave. We show that published measurements of the cooling rate dependence of the magnetisation are inconsistent with paramagnetic impurities. Triplet pairing is ruled out by NMR and upper critical field experiments. Thus if the disorder is non-magnetic then this implies that l ≥ 2, in which case Occam's razor suggests that d-wave pairing is realised in both β-(BEDT-TTF)2X and κ-(BEDT-TTF)2X. However, particularly given the proximity of these materials to an antiferromagnetic Mott transition, it is possible that the disorder leads to the formation of local magnetic moments via some novel mechanism. Thus we conclude that either β-(BEDT-TTF)2X and κ-(BEDT-TTF)2X are d-wave superconductors or else they display a novel mechanism for the formation of localised moments, possibly related to the competition between the antiferromagnetic and superconducting grounds states. We suggest systematic experiments to differentiate between these two scenarios.

show abstract

Section: B Non-magnetic Disorder In Other Superconductorsmentioning

confidence: 99%

Dependence of the superconducting transition temperature of organic molecular crystals on intrinsically nonmagnetic disorder: A signature of either unconventional superconductivity or the atypical formation of magnetic moments

Powell

McKenzie

2004

Phys. Rev. B

View full text Add to dashboard Cite

show abstract

Upper critical field and isotope effect in the oxide superconductors

Pérez-González

Ćarbotte

1992

J Low Temp Phys

View full text Add to dashboard Cite

In a model for which the pairing is due mainly to an electronic mechanism supplemented by a small phonon contribution, we study the isotope effect exhibited by the upper critical magnetic field He2 and compare with the critical temperature. When paramagnetic impurities are added, we find very different behaviours from that predicted in a pure phonon model The alignment of the paramagnetic spin by the external magnetic field as well as Pauli limiting is neglected in our calculations.

show abstract

Quasiclassical theory of the upper critical field of high-field superconductors. Application to momentum-dependent scattering

Rieck

Scharnberg

Schopohl³

1991

J Low Temp Phys

View full text Add to dashboard Cite

Superconducting alloys with paramagnetic impurities I: Theory of the upper critical field

Cited by 9 publications

References 14 publications

Dependence of the superconducting transition temperature of organic molecular crystals on intrinsically nonmagnetic disorder: A signature of either unconventional superconductivity or the atypical formation of magnetic moments

Dependence of the superconducting transition temperature of organic molecular crystals on intrinsically nonmagnetic disorder: A signature of either unconventional superconductivity or the atypical formation of magnetic moments

Upper critical field and isotope effect in the oxide superconductors

Quasiclassical theory of the upper critical field of high-field superconductors. Application to momentum-dependent scattering

Contact Info

Product

Resources

About