Transport properties of iron at Earth’s core conditions: The effect of spin disorder

0482166 - FZÚ 2018 RIV US eng J - Článek v odborném periodiku
Drchal, Václav - Kudrnovský, Josef - Wagenknecht, D. - Turek, I. - Khmelevskyi, S.
Transport properties of iron at Earth’s core conditions: The effect of spin disorder.
Physical Review B. Roč. 96, č. 2 (2017), s. 1-5, č. článku 024432. ISSN 2469-9950. E-ISSN 2469-9969
Grant CEP: GA ČR GA15-13436S
Grant ostatní: GA MŠk(CZ) LM2015042; Ga MŠk(CZ) LM2015070
Institucionální podpora: RVO:68378271
Klíčová slova: Earth's core * electrical conductivity * spin-disorder resistivity * violation of Matthiessen rule
Obor OECD: Condensed matter physics (including formerly solid state physics, supercond.)
Impakt faktor: 3.813, rok: 2017

We show, by considering bcc iron and an iron-rich iron-silicon alloy as a representative of the Earth’s core composition and applying first-principles modeling, that the spin disorder at the Earth’s core conditions not considered previously provides an essential contribution, of order 20 μΩ cm, to the electrical resistivity. This value is comparable in magnitude with the electron-phonon and with the recently estimated electron-electron scattering contributions. The origin of the spin-disorder resistivity (SDR) consists of the existence of fluctuating local moments that are stabilized at high temperatures by the magnetic entropy even at pressures at which the ground state of iron is nonmagnetic. We find that electron-phonon and SDR contributions are not additive at high temperatures. We thus observe a large violation of the Matthiessen rule.
Trvalý link: http://hdl.handle.net/11104/0277561