Intertwined symmetry of the magnetic modulation and the flux-line lattice in the superconducting state of TmNi2B2C

Eskildsen, M. R.; Harada, Ken; Gammel, P. L.; Abrahamsen, Asger Bech; Andersen, N.H.; Ernst, G.; Ramirez, A. P.; Bishop, David J.; Mortensen, K.; Naugle, D. G.; Rathnayaka, K. D. D.; Canfield, Paul C.

doi:10.1038/30447

Cited by 84 publications

(67 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At low temperature the magnetic moments are along the c axis, which consequently is the direction of the maximum magnetic susceptibility [5,6]. For magnetic fields applied parallel to the c axis, H c2 shows a nonmonotonic behavior, reaching a maximum near T 5 K and 0 H c2 1 T due to the Tm sublattice magnetization, decreasing upon approaching the magnetic ordering temperature and finally increasing again below T N [1,5]. Previous studies showed simultaneous magnetic and VL symmetry transitions below T N , as well as peaks in the VL reflectivity associated with the magnetic transitions [1].…”

mentioning

confidence: 99%

“…The antiferromagnetic members of the intermetallic nickelborocarbide superconductors RNi 2 B 2 C (R Ho, Er, or Tm) have proved especially rich vehicles for such studies, displaying, e.g., intertwined magnetic and superconducting transitions as well as subtle changes in the superconducting characteristic length scales associated with the onset of antiferromagnetic ordering [1][2][3]. The exchange interaction H sf ÿI g J ÿ 1 J s between the 4f localized moment J and the conduction electron spin s (g J is the Landé g factor and I is the exchange integral) is important in understanding systematic changes of both superconducting and magnetic transition temperatures [4].…”

mentioning

confidence: 99%

“…The form factor F q h;k is calculated from the internal field distribution B r P h;k F q h;k exp iq h;k r with the wave vectors q h;k hq 1 kq 2 , q 1 2 =a; ÿ =a y ; 0 , and q 2 2 =a; =a y ; 0 , corresponding to VL unit vectors a=2; a y and a=2; ÿa y . The intensity of the main peak at h; k 1; 0 gives the fundamental component F q 0;1 .…”

mentioning

confidence: 99%

See 2 more Smart Citations

Pauli Paramagnetic Effects on Vortices in SuperconductingTmNi2B2C

et al. 2007

Self Cite

View full text Add to dashboard Cite

show abstract

mentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Pauli Paramagnetic Effects on Vortices in SuperconductingTmNi2B2C

et al. 2007

Self Cite

View full text Add to dashboard Cite

show abstract

“…[5][6][7][8] This is not expected for the local model with isotropic intervortex interactions and thereby suggests the importance of considering electronic structure (or the Fermi surface) and the associated nonlocal corrections in the specific compound.…”

mentioning

confidence: 99%

Nonlocal effects and shrinkage of the vortex core radius inYNi2B2Cprobed by muon spin rotation

et al. 2002

View full text Add to dashboard Cite

The magnetic field distribution in the vortex state of YNi2B2C has been probed by muon spin rotation (µSR). The analysis based on the London model with nonlocal corrections shows that the vortex lattice has changed from hexagonal to square with increasing magnetic field H. At low fields the vortex core radius, ρv(H), decreases with increasing H much steeper than what is expected from the √ H behavior of the Sommerfeld constant γ(H), strongly suggesting that the anomaly in γ(H) primarily arises from the quasiparticle excitations outside the vortex cores.74.60. Ec, 76.75.+i The recent studies of the flux-line lattice (FLL) state in ordinary s-wave superconductors have revealed that the electronic structure of vortices is much more complicated than that of a simple array of rigid cylinders containing normal electrons. One of the unexpected phenomena within this conventional model is the non-linearity in the magnetic field dependence of the Sommerfeld constant γ(H) (electronic specific heat coefficient) observed in CeRu 2 1 , NbSe 2 2 , and YNi 2 B 2 C 2 . According to the above simple model where the quasiparticle excitations are confined within the cores of vortices (with a radius ξ) in s-wave superconductors, one would expect that γ(H) is proportional to the number of vortices per unit cell and thus to the applied magnetic field H. However, experiments have revealed that this is not the case for any of the above compounds. 1,2 Instead, they find a field dependence like γ(H) ∝ √ H which is expected for d-wave superconductors having more extended quasiparticle excitations along nodes in the energy gap. The recent study on the effect of doping in YNi 2 B 2 C and NbSe 2 indicates that the anomalous field dependence is observed only in the clean limit 2 , suggesting the importance of nonlocal effects in understanding the field dependence of γ(H). Moreover, it has been reported that the vortex core radius depends on applied magnetic field and shrinks at higher fields in NbSe 2 3 and in CeRu 2 4 .Another complication especially for borocarbides (RNi 2 B 2 C, R = rare earth) is that a square FLL is formed in some of these compounds at high magnetic fields, whereas a hexagonal FLL is realized at low fields. 5-8 This is not expected for the local model with isotropic intervortex interactions and thereby suggests the importance of considering electronic structure (or the Fermi surface) and the associated nonlocal corrections in the specific compound.We report on µSR measurements of the magnetic field dependence of theâ-b magnetic penetration depth λ, the effective vortex core radius ρ v , and the apex angle of the FLL θ in single crystalline YNi 2 B 2 C. We demonstrate that the proper reconstruction of the field profile with a square FLL is obtained from the µSR spectra only when the nonlocal corrections are considerred. 9 The field dependence of λ turned out to be linear over the entire magnetic field range of observation. More importantly, it was found that ρ v shrinks sharply with increasing magnetic field and levels ...

show abstract

“…6,7,8,9 The transition from square to hexagonal vortex lattice occurs due to the competition between sources of anisotropy and vortex-vortex interactions. The repulsive nature of the vortex interaction favors the hexagonal Abrikosov lattice, whose vortex spacing is larger than that of a square lattice.…”

mentioning

confidence: 99%

Anomalous paramagnetic effects in the mixed state ofLuNi2B2C

et al. 2005

Self Cite

View full text Add to dashboard Cite

Anomalous paramagnetic effects in dc magnetization were observed in the mixed state of LuNi2B2C, unlike any reported previously. It appears as a kink-like feature for H ≥ 30 kOe and becomes more prominent with increasing field. A specific heat anomaly at the corresponding temperature suggests that the magnetization anomaly is due to a true bulk transition. A magnetic flux transition from a square to an hexagonal lattice is consistent with the anomaly.In cuprate (high-T c ) superconductors, high-transition temperatures (T c ) and short coherence lengths (ξ) lead to large thermal fluctuation effects, opening a possibility for melting of the flux line lattice (FLL) at temperatures well below the superconducting transition temperature. A discontinuous step in dc magnetization and a sudden, kink-like drop in resistivity signified the first order nature of the melting transition from the vortex lattice into a liquid. 1,2,3 In conventional type II superconductors, with modest transition temperatures and large coherence lengths, vortex melting is also expected to occur in a very limited part of the phase diagram, 4 but it has yet to be observed experimentally. In the rare-earth nickel borocarbides RNi 2 B 2 C (R = Y, Dy, Ho, Er, Tm, Lu), the coherence lengths (ξ ∼ = 10 2Å ) and superconducting transition temperatures (16.1 K for R = Lu) lie between these extremes, suggesting that the vortex melting will be observable and may provide further information on vortex dynamics. Indeed, Mun et al. 5 reported the observation of vortex melting in YNi 2 B 2 C, based on a sharp, kink-like drop in electrical resistivity.Recently, a magnetic field-driven FLL transition has been observed in the tetragonal borocarbides. 6,7,8,9 The transition from square to hexagonal vortex lattice occurs due to the competition between sources of anisotropy and vortex-vortex interactions. The repulsive nature of the vortex interaction favors the hexagonal Abrikosov lattice, whose vortex spacing is larger than that of a square lattice. The competing anisotropy, which favors a square lattice, can be due to lattice effects (fourfold Fermi surface anisotropy), 10 unconventional superconducting order parameter, 11 or an interplay of the two. 12,13 In combination with non-negligible fluctuation effects, the competition leads to unique vortex dynamics right below the H c2 line in the borocarbides, namely a reentrant vortex lattice transition. 9 Fluctuation effects near the upper critical field line wash out the anisotropy effect, stabilizing the Abrikosov hexagonal lattice. 14,15 Here, we report the first observation of paramagnetic effects in the dc magnetization M of the mixed state of LuNi 2 B 2 C. The kink-like feature in M and the corresponding specific heat feature for H ≥ 30 kOe signify the reentrant FLL transition, which is consistent with the low-field FLL transition line inferred from small angle neutron scattering (SANS). 9 Single crystals of LuNi 2 B 2 C were grown in a Ni 2 B flux as described elsewhere 16 and were post-growth annealed at T = 10...

show abstract

Intertwined symmetry of the magnetic modulation and the flux-line lattice in the superconducting state of TmNi2B2C

Cited by 84 publications

References 18 publications

Pauli Paramagnetic Effects on Vortices in SuperconductingTmNi2B2C

Pauli Paramagnetic Effects on Vortices in SuperconductingTmNi2B2C

Nonlocal effects and shrinkage of the vortex core radius inYNi2B2Cprobed by muon spin rotation

Anomalous paramagnetic effects in the mixed state ofLuNi2B2C

Contact Info

Product

Resources

About