13C NMR observation of extreme type-II superconductivity in K3C60: A method of estimating penetration depth

Susumu Sasaki; C. W. Chu

doi:10.1103/PhysRevB.61.6366

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13C NMR observation of extreme type-II superconductivity in K3C60: A method of estimating penetration depth

Susumu Sasaki, C. W. Chu

DOI 10.1103/PhysRevB.61.6366 · Physical Review B

T1

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Abstract

We present a method of estimating the penetration depth λ(0) for extreme type-II superconductors that exhibit powder-pattern NMR line shapes in which the anisotropy of the shifts dominates the effect of magnetic field distribution. In this method, we regard the increase in the broadening, not that in the width of the overall line shape, as the field distribution defined in the Pincus’s formula [Pincus et al., Phys. Lett. 13, 21 (1964)]. Applying this method to the previous result of 13C NMR line shapes for K3C60, we found that λ(0)>~ 8100 Å, which is consistent with the value of 8900 Å recently obtained from precise low-field magnetization measurements [Buntar et al., Phys. Rev. B 54, R9651 (1996)]. This validates not only the present method but also the data and analyses of the 13C NMR line shapes so far. We also discuss why values of λ(0) smaller than the real one were reported in the early stage of the study of A3C60 superconductivity.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
K3C60 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown