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The electrical resistivity of solid and liquid Fe at pressures up to 7 GPa

1989; American Geophysical Union; Volume: 94; Issue: B5 Linguagem: Inglês

10.1029/jb094ib05p05887

2156-2202

Richard A. Secco, H. H. Schloessin,

earthquake and tectonic studies

The electrical resistivity of pure solid and liquid Fe has been measured at pressures up to 7 GPa in a large volume cubic anvil press. In conjunction with the four‐wired method, a novel technique of potential lead attachment was employed to measure the resistivity of 0.020‐in‐diameter Fe wire samples. Both the temperature and pressure coefficients of resistivity have been determined for solid and liquid Fe. The temperature coefficients of resistivity (TCR) in the liquid state are of the order of 10 −4 K −1 and show an abrupt increase at approximately 5.2 GPa corresponding to the δ‐γ‐liquid triple point. We have interpreted this discontinuity in the TCR to be a reflection of local atomic structure in the liquid state which is reminiscent of the parent solid structure. By analogy, this result can be applied to the geophysically more important γ‐ε‐liquid triple point. By examining the fundamental effects of pressure and temperature on the density of states function and their ranges we arrive at an estimate of 1.2–1.5 × 10 −6 Ωm for the electrical resistivity of pure Fe at the pressures and temperatures expected in the Earth's core.