Low-Temperature Penetration Depth of {kappa}-(ET){sub 2}Cu[N(CN) {sub 2}]Br and {kappa}-(ET){sub 2}Cu(NCS){sub 2}
We present high-precision measurements of the penetration depth of single crystals of {kappa}-(ET){sub 2}Cu[N(CN){sub 2}]Br and {kappa}-(ET){sub 2}Cu(NCS){sub 2} at temperatures down to 0.4 K. We find that, at low temperatures, the in-plane penetration depth ({lambda}{sub (parallel} {sub sign)}) varies as a fractional power law, {lambda}{sub (parallel} {sub sign)}{approx}T{sup (3/2)}. While this may be taken as evidence for novel pair excitation processes, we show that the data are also consistent with a quasilinear variation of the superfluid density, as is expected for a d -wave superconductor with impurities or a small residual gap. Our data for the interplane penetration depth show similar features and give a direct measurement of the absolute value, {lambda}{sub (perpendicular} {sub sign)}(0)=100{+-}20 {mu}m . (c) 1999 The American Physical Society.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL
- OSTI ID:
- 20217962
- Journal Information:
- Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 20 Vol. 83; ISSN 0031-9007; ISSN PRLTAO
- Country of Publication:
- United States
- Language:
- English
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