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Unconventional superconductivity and non-Fermi liquid behaviour of -iron at high pressure

2004; IOP Publishing; Volume: 16; Issue: 14 Linguagem: Inglês

10.1088/0953-8984/16/14/021

1361-648X

A. T. Holmes, D. Jaccard, G. Behr, Y. Inada, Yoshichika Ōnuki,

High-pressure geophysics and materials

We report further resistive measurements under pressure of samples of iron from multiple sources. The normal state resistivity of ε-iron varied as ρ0+AT5/3 at low temperature over the entire superconducting pressure domain. The superconductivity could be destroyed by mechanical work, and was restored by annealing, demonstrating sensitivity to the residual resistivity ρ0. There is a strong correlation between the ρ0 and A coefficients and the superconducting critical temperature Tc. The critical field Bc2 corresponding to the maximum Tc was found to be 0.73 T, implying a coherence length of about 20 nm, i.e. slightly shorter than the electronic mean free path. Within the partial resistive transition there was a significant current dependence, with V (I) = a(I−I0)+bI2, and , possibly indicating flux-flow resistivity, even in the absence of an externally applied magnetic field.