Competition between magnetism and superconductivity in CeCu{sub 2}Si{sub 2}
- Institute for Particle Physics, ETH Zuerich, CH-5232 Villigen PSI (Switzerland)
- Institut fuer Festkoerperphysik, TH Darmstadt, 64289 Darmstadt (Germany)
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
- University of California, Riverside, California 92521-0413 (United States)
- Kamerlingh Onnes Laboratory, Leiden University, 2300 RA Leiden (The Netherlands)
The interplay between superconductivity and magnetism in CeCu{sub 2}Si{sub 2} has been investigated by means of microprobe, muon spin rotation and relaxation ({mu}SR), and specific-heat measurements on four slightly off-stoichiometric polycrystalline samples Ce{sub 1+x}Cu{sub 2+y}Si{sub 2}. Microprobe analysis reveals that within the errors ({plus_minus}3{percent}) the main phases of all four samples exhibit the ideal stoichiometry 1:2:2 and their relative composition varies by less than 2{percent}. Muon spin rotation and relaxation measurements, however, reveal pronounced differences in their ground states. The nonsuperconducting sample Ce{sub 0.99}Cu{sub 2.02}Si{sub 2} exhibits a phase transition at T{sub m}=0.67 K to a magnetically ordered ground state of unknown structure, with a lower limit on the size of the frozen moments {mu}{approx}0.2{mu}{sub B}. For T{lt}T{sub m} slow residual fluctuations of these moments at a rate {nu}{approx}3 MHz are observed. In the three superconducting samples comparable magnetic behavior is found in reduced volume fractions. Paramagnetic and magnetic regions are distributed inhomogeneously in these samples, the relative volume fractions being strongly sample and temperature dependent. In all samples considerable volume fractions remain magnetic down to T=60 mK. The present data provide evidence that superconductivity sets in first in the paramagnetic regions, and, on further cooling, reduces the magnetically ordered volume fraction. Superconductivity and magnetic order do not appear to spatially coexist, but compete in CeCu{sub 2}Si{sub 2}. {copyright} {ital 1997} {ital The American Physical Society}
- OSTI ID:
- 549304
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 56, Issue 2; Other Information: PBD: Jul 1997
- Country of Publication:
- United States
- Language:
- English
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