Materials that can in principle exhibit both superconductivity and ferromagnetism are caught in a dilemma: both states represent long-range order, but are in general mutually exclusive. When the material favours a ground state with a large magnetic moment, as is the case for Er4Rh4B (ref. 1), superconductivity is destroyed. For superconductivity to persist, the magnetic structure would need to adopt an antiferromagnetic modulation of short enough wavelength to ensure a small net moment on the length scale of the superconducting coherence length. The intermetallic borocarbide superconductors2,3,4 RNi2B2C (where R is a rare-earth element) have shed new light on this balance between magnetism and superconductivity. The response of these materials in the superconducting state to a magnetic field is dominated by the formation of a flux-line lattice—a regular array of quantized magnetic vortices whose symmetry and degree of order are easily modified and thus can be expected to interact with an underlying magnetic modulation. In TmNi2B2C, superconductivity and antiferromagnetic modulated ordering coexist below 1.5 K (5–7). Here we present the results of a small-angle neutron-scattering study of this compound which show that the structure of the magnetic modulation and the symmetry of the flux-line lattice are intimately coupled, resulting in a complex phase diagram.
Subscribe to Journal
Get full journal access for 1 year
only $3.90 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
Crabtree, G. W. et al. Anisotropic superconducting and magnetic properties of a single crystal of ErRh4B4. Phys. Rev. Lett. 49, 1342–1345 (1982).
Siegrist, T. et al. The crystal structure of superconducting LuNi2B2C and the related phase LuNiBC. Nature 367, 254–256 (1994).
Cava, R. J. et al. Superconductivity in the quaternary intermetallic compounds LnNi2B2C. Nature 367, 252–253 (1994).
Nagarajan, R. et al. Bulk superconductivity at an elevated temperature (Tc≈ 12 K) in a nickel containing alloy system Y-Ni-B-C. Phys. Rev. Lett. 72, 274–277 (1994).
Cho, B. K. et al. Magnetic and superconducting properties of single-crystal TmNi2B2C. Phys. Rev. B 52, 3676–3683 (1995).
Lynn, J. W. et al. Magnetic order and crystal structure in the superconducting RNiB2C2materials. Phys. Rev. B 55, 6584–6598 (1997).
Sternlieb, B. et al. Single crystal diffraction study of the magnetic structure of TmNi2B2C. J. Appl. Phys. 81, 4937–4939 (1997).
Cho, B. K. et al. Magnetism and superconductivity in single crystal ErNi2B2C. Phys. Rev. B 52, 3684–3695 (1995).
Yaron, U. et al. Microscopic coexistence of magnetism and superconductivity in ErNi2B2C. Nature 382, 236–238 (1996).
Eskildsen, M. R. et al. Observation of a field-driven structural phase transition in the flux line lattice in ErNi2B2C. Phys. Rev. Lett. 78, 1968–1971 (1997).
Eskildsen, M. R. et al. Structural stability of the square flux line lattice in YNi2B2C and LuNi2B2C studied with small angle neutron scattering. Phys. Rev. Lett. 79, 487–490 (1997).
Gammel, P. L. et al. Small angle neutron scattering study of the magnetic flux-line lattice in single crystal 2H-NbSe2. Phys. Rev. Lett. 72, 278–282 (1994).
Kleiman, R. N. et al. Neutron diffraction from the vortex lattice in the heavy-fermion superconductor UPt3. Phys. Rev. Lett. 69, 3120–3124 (1992).
Gray, K. E. Ginzburg-Landau equations, interphase surface energy, and the intermediate state of superconductors with a paramagnetic normal state. Phys. Rev. B 27, 4157–4160 (1983).
Tachiki, M., Matsumoto, H. & Umezawa, H. Mixed state in magnetic superconductors. Phys. Rev. B 20, 1915–1927 (1979).
Kogan, V. G. et al. Vortex lattice transitions in borocarbides. Phys. Rev. B 55, R8693–R8696 (1997).
De Wilde, Y. et al. Scanning tunneling microscopy observation of a square Abrikosov lattice in LuNi2B2C. Phys. Rev. Lett. 78, 4273–4277 (1997).
Canfield, P. C. Angular dependence of metamagnetic transitions in HoNi2B2C. Phys. Rev. B 55, 970–976 (1997).
Peng, Z. Q., Krug, K. & Winzer, K. Large hysteresis effect and reentrant behavior in DyNi2B2C at temperatures T < 2 K. Phys. Rev. Lett.(submitted).
We thank C. Stassis, P. Hedegård and J. Jensen for discussions. This work was supported by NATO. M.R.E. is supported by the Danish Research Academy, D.G.N. is supported by the Robert A. Welch Foundation and P.C.C. is supported by the Director of Energy Research, Office of Basic Energy Science.
About this article
Cite this article
Eskildsen, M., Harada, K., Gammel, P. et al. Intertwined symmetry of the magnetic modulation and the flux-line lattice in the superconducting state of TmNi2B2C. Nature 393, 242–245 (1998). https://doi.org/10.1038/30447
Reviews of Modern Physics (2019)
Vortex lattice and vortex bound states in CsFe2As2 investigated by scanning tunneling microscopy/spectroscopy
Physical Review B (2018)
Applied Physics Letters (2017)
Subsurface bending and reorientation of tilted vortex lattices in bulk isotropic superconductors due to Coulomb-like repulsion at the surface
Physical Review B (2017)
Simultaneous evidence for Pauli paramagnetic effects and multiband superconductivity inKFe2As2by small-angle neutron scattering studies of the vortex lattice
Physical Review B (2016)