eprintid: 1367040 rev_number: 40 eprint_status: archive userid: 608 dir: disk0/01/36/70/40 datestamp: 2012-10-10 19:19:34 lastmod: 2021-10-04 01:18:47 status_changed: 2012-10-10 19:19:34 type: article metadata_visibility: show item_issues_count: 0 creators_name: Cote, AS creators_name: Vocadlo, L creators_name: Brodholt, JP title: Ab initio simulations of iron-nickel alloys at Earth's core conditions ispublished: pub divisions: UCL divisions: B04 divisions: C06 divisions: F57 keywords: iron, nickel, Earth's core, ab initio note: This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. abstract: We report ab initio density functional theory calculations on iron–nickel (FeNi) alloys at conditions representative of the Earth's inner core. We test different concentrations of Ni, up to ∼39 wt% using ab initio lattice dynamics, and investigate the thermodynamic and vibrational stability of the three candidate crystal structures (bcc, hcp and fcc). First of all, at inner core pressures, we find that pure Fe transforms from the hcp to the fcc phase at around 6000 K. Secondly, in agreement with low pressure experiments on Fe–Ni alloys, we find the fcc structure is stabilised by the incorporation of Ni under core pressures and temperatures. Our results show that the fcc structure may, therefore, be stable under core conditions depending on the temperature in the inner core and the Ni content. Lastly, we find that within the quasi-harmonic approximation, there is no stability field for FeNi alloys in the bcc structure under core conditions. date: 2012-09 official_url: http://dx.doi.org/10.1016/j.epsl.2012.06.025 vfaculties: VMPS vfaculties: VMPS oa_status: green language: eng primo: open primo_central: open_green verified: verified_manual elements_source: WoS-Lite elements_id: 524980 doi: 10.1016/j.epsl.2012.06.025 lyricists_name: Brodholt, John lyricists_name: Cote, Alexander lyricists_name: Vocadlo, Lidunka lyricists_id: JPBRO15 lyricists_id: ASCOT13 lyricists_id: NLVOC18 full_text_status: public publication: Earth and Planetary Science Letters volume: 345-34 pagerange: 126 - 130 issn: 0012-821X citation: Cote, AS; Vocadlo, L; Brodholt, JP; (2012) Ab initio simulations of iron-nickel alloys at Earth's core conditions. Earth and Planetary Science Letters , 345-34 126 - 130. 10.1016/j.epsl.2012.06.025 <https://doi.org/10.1016/j.epsl.2012.06.025>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/1367040/1/1367040.pdf