Magnetic correlations and crystal-field levels in the superconductor ()
- 1 January 1980
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review B
- Vol. 21 (1), 70-78
- https://doi.org/10.1103/physrevb.21.70
Abstract
Neutron scattering studies have been carried out to investigate the atomic magnetic properties of the "magnetic" superconductor ( ) . At low temperatures we observe the appearance of elastic or quasielastic magnetic scattering at small momentum transfers, indicating the development of ferromagnetic correlations. The temperature and wave-vector dependence of this scattering can be described to a good approximation by an Ornstein-Zernike correlation function over the entire range of wave vectors (0.035-0.20 ) and temperatures (0.05-4.2 K) explored. The range of the spatial correlations increases smoothly with decreasing temperature and suggests the onset of ferromagnetism at ∼ 0.5 K. However, below 0.5 K, ceases to increase, saturating at a value of 80 Å with no detectable change in the scattering below that temperature. Thus there is no transition to conventional long-range ferromagnetic order. There is also no indication in the magnetic scattering of the onset of superconductivity at 1.6 K. Measurements of the inelastic magnetic scattering reveal a number of crystal-field transitions, demonstrating that the crystalline electric field removes the 17-fold degeneracy of the free ion. The nature of the splittings can be understood on the basis of a crystal field with cubic symmetry, and the ground state is found to be the triply degenerate state, which possesses a magnetic moment. At low temperatures additional magnetic inelastic scattering is observed at low energies; this suggests that there are substantial exchange effects even though the characteristic magnetic temperature (0.5 K) is very small.
Keywords
This publication has 27 references indexed in Scilit:
- Spontaneous magnetic order in below the superconducting transition temperaturePhysical Review B, 1980
- Magnetic ordering in the superconducting state of rare earth molybdenum sulphides, (RE)1.2Mo6S8 (RE = Tb, Dy and Er)Solid State Communications, 1977
- Coexistence of superconductivity and long-range antiferromagnetic order in the compound ErxMo6Se8Solid State Communications, 1977
- Destruction of superconductivity by magnetic ordering in Ho1.2Mo6S8Solid State Communications, 1977
- Destruction of Superconductivity at the Onset of Long-Range Magnetic Order in the Compound ErPhysical Review Letters, 1977
- SuperconductivityApplied Physics A, 1976
- On the preparation and the superconducting properties of CeRu2 and its mixed crystals with ARu2 (A = rare-earth element) and CeB2 (B = Mn, Fe-group or Pt-group element)Physica, 1971
- Possible coexistence of superconductivity and ferromagnetism in mixed crystals of the type Ce1−xTbxRu2Physics Letters A, 1970
- Über die präparation und das supraleitende verhalten von CeRu2 und seiner Gd-, Mn-, Fe-, Co- und Ni-haltigen mischphasenJournal of Physics and Chemistry of Solids, 1970
- Ferromagnetic SuperconductorsPhysical Review Letters, 1958