μSR studies of intercalated HfNCl superconductor

• Published in: Physica. B, Condensed matter Vol. 289; pp. 389 - 392
• Main Authors: Uemura, Y.J, Fudamoto, Y, Gat, I.M, Larkin, M.I, Luke, G.M, Merrin, J, Kojima, K.M, Itoh, K, Yamanaka, S, Heffner, R.H, MacLaughlin, D.E
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-08-2000
• Subjects: HfNCl; Penetration depth; Superconductivity; Superconductivity; Penetration depth; HfNCl
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/S0921-4526(00)00418-X

Muon spin relaxation measurements of the magnetic field penetration depth
λ have been performed in a quasi two-dimensional (2-d) superconductor based on HfNCl intercalated with Li and organic molecules. The relaxation rate
σ(T→0)∼0.5
μs
−1
was obtained with transverse fields applied perpendicular to the aligned HfN planes. Using the relation
σ∝λ
−2∝n
s2d
/m
∗
(2-d superconducting carrier density/effective mass), we deduced the 2-d Fermi temperature
T
F2d. The ratio
T
c/
T
F2d for the HfNCl-(Li) system is very close to those in two other quasi-2-d superconductors, YBa
2Cu
3O
7 and (BEDT-TTF)
2-X. Compared to the Kosterlitz–Thouless (KT) transition temperature
T
KT=
T
F2d/8 for the limit of strong coupling,
T
c's of these systems are reduced by a factor of 3–4, indicating the importance of carrier overlapping and/or 3-d coupling.