Bi₂Sr₂CaCu₂0_8+x

Value	Technique	Reference	Comments
Penetration depth (λ)
λab(0) = 2600 Å ( Tc = 91 K)	microwave surface impedance	T. Jacobs et al, PRL 75, 4516 (1995)	&Delta&lambdaab(T) ia shown in Fig. 2. At low temperatures, &Delta&lambdaab(T)∝T, which reflects an in-plane SC order parameter with nodes in the gap, d[&Delta&lambdaab(T)]/dT &sim 10Å/K leads to &lambdaab(T=0)&sim 2600Å
λab(0)=2700Å	lower critical field HC1 measurement	M. Nideröst et al, PRL 81, 3231 (1998)	Isothermal magnetization were measured for configurations of negligible geometrical barriers. At very low temperatures, creep over surface barriers is avoided and real HC1 is used to calculate λab(0).
λab(0) ≅ 2100Å (Tc = 85K)	reversible magnetization	V. G. Kogan et al, PRL 70, 1870 (1993)	By taking fluctuations into account, reversible magnetization data are used to determine λab(T) (See Fig. 2).
λab(0) =1800 Å (Tc = 84 K)	μSR	S. L. Lee et al, PRL 71, 3862 (1993)	The analysis of μSR line shapes at flux melting point (Eq. 2) yields λab(0).