Tetrataenite is a native metal alloy composed of chemically-ordered L10-type FeNi, recognized as a mineral in 1980.[5] The mineral is named after its tetragonal crystal structure and its relation to the iron-nickel alloy, taenite, which is chemically disordered (A1) phase with an underlying fcc lattice.[6] Tetrataenite is one of the mineral phases found in meteoric iron.[7][3][8] Before its discovery in meteoritic samples, experimental synthesis of the L10 phase was first reported in 1962 by Louis Néel and co-workers, following neutron irradiation of a chemically disordered FeNi sample under an applied magnetic field.[9][10][11] Compared to the magnetically soft, chemically disordered A1 phase (taenite), the tetragonal L10 structure of tetrataenite leads to good hard magnetic properties, including a large uniaxial magnetocrystalline anisotropy energy.[10][12] Consequently, it is under consideration for applications as a rare-earth-free permanent magnet.[13]

Tetrataenite
Silvery-bright tetrataenite crystals
General
CategoryNative element minerals
Formula
(repeating unit)
FeNi
IMA symbolTtae[1]
Strunz classification1.AE.10
Crystal systemTetragonal
Crystal classDomatic (m)
(same H-M symbol)
Space groupPm
Unit cell22.92 ų
Identification
Formula mass57.27 gm
Colorgray white, silver white
Crystal habitGranular – Common texture observed in granite and other igneous rock
Cleavagenone
Fracturemalleable
Mohs scale hardness3.5
Lustermetallic
Streakgray
Diaphaneityopaque
Density8.275
Common impuritiesCo, Cu, P
References[2][3][4]

[1]

[2]

Formation

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Tetrataenite forms naturally in iron meteorites that contain taenite that are slow-cooled at a rate of a few degrees per million years, which allows for ordering of the Fe and Ni atoms.[5][14] It is found most abundantly in slow-cooled chondrite meteorites,[15] as well as in mesosiderites.[5] At high (as much as 52%) Ni content and temperatures below 320 °C (the order-disorder transition temperature[9]), tetrataenite is broken down from taenite and distorts its face centered cubic crystal structure to form the tetragonal L10 structure.[16][14]

It is reported that the L10 phase can be synthetically produced by neutron- or electron-irradiation of chemically disordered (A1) FeNi below 593 K,[9][10][11] by hydrogen-reduction of nanometric NiFe2O4,[14] by combined application of mechanical stress and magnetic field during annealing of the chemically disordered A1 phase,[17] or by crystallization of Fe−Ni alloys in the presence of traces of phosphorus.[18]

In 2015, it was reported that tetrataenite was found in a terrestrial rock – a magnetite body from the Indo-Myanmar ranges of northeast India.[14]

Potential laboratory protocols for bulk synthesis

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Applied Stress and Magnetic Field

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It has been reported that the combined application of mechanical stress and a modest magnetic field during the annealing process can accelerate the formation of the atomically ordered L10 phase in bulk samples.[17]

Addition of Phosphorus

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In 2022, it was reported that mixing iron and nickel together in specific quantities, with a phosphorus catalyst, and smelting the mixture, forms tetrataenite in bulk quantities, in seconds.[19][20] These claims raised hopes that some of the technologies which currently require the use of magnetic alloys containing rare earths metals may be achievable using magnets made of tetrataenite as an alternative, which would reduce dependence on toxic, environmentally harmful rare earth mines.[21] However, at present, the reported findings are yet to be independently replicated by other experimental groups.

Crystal structure

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Tetrataenite has a highly ordered crystal structure,[16] appearing creamy in color and displaying optical anisotropy.[5] Its appearance is distinguishable from taenite, which is dark gray with low reflectivity.[14] FeNi easily forms into a cubic crystal structure, but does not have magnetic anisotropy in this form. Three variants of the L10 tetragonal crystal structure have been found, as chemical ordering can occur along any of the three axes.[13]

Magnetic properties

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Tetrataenite displays permanent magnetization, in particular, high coercivity.[22] It has a large uniaxial magnetocrystalline anisotropy[12] and theoretical magnetic energy product, the maximum amount of magnetic energy stored, over 335 kJ m−3.[22] The L10 phase has a theoretical Curie temperature of over 1000 K,[12] resulting in a magnetic anisotropy which is predicted to remain large up to and beyond room temperature.

Applications

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Tetrataenite is a candidate for replacing rare-earth permanent magnets such as samarium and neodymium since both iron and nickel are earth-abundant and inexpensive.[23]

See also

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References

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  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ "Mineralienatlas – Fossilienatlas". www.mineralienatlas.de. Retrieved 1 April 2023.
  3. ^ a b "Tetrataenite: Mineral information, data and localities". Retrieved 1 April 2023.
  4. ^ "Tetrataenite". webmineral.com.
  5. ^ a b c d Clarke, Roy S.; Scott, Edward R. D. (March 6, 1980). "Tetrataenite – ordered FeNi, a new mineral in meteorites" (PDF). American Mineralogist. 65: 624–630.
  6. ^ "Tetrataenite: Tetrataenite mineral information and data". www.mindat.org. Retrieved 2018-03-30.
  7. ^ "Tetrataenite". webmineral.com.
  8. ^ "Handbook of Mineralogy – Tetrataenite" (PDF). Retrieved 1 April 2023.
  9. ^ a b c Paulevé, J.; Dautreppe, D.; Laugier, J.; Néel, L. (1962-10-01). "Une nouvelle transition ordre-désordre dans Fe-Ni (50-50 )". Journal de Physique et le Radium (in French). 23 (10): 841–843. doi:10.1051/jphysrad:019620023010084100. ISSN 0368-3842.
  10. ^ a b c Néel, L.; Pauleve, J.; Pauthenet, R.; Laugier, J.; Dautreppe, D. (1964-03-01). "Magnetic Properties of an Iron—Nickel Single Crystal Ordered by Neutron Bombardment". Journal of Applied Physics. 35 (3): 873–876. doi:10.1063/1.1713516. ISSN 0021-8979.
  11. ^ a b Paulevé, J.; Chamberod, A.; Krebs, K.; Bourret, A. (1968-02-01). "Magnetization Curves of Fe–Ni (50–50) Single Crystals Ordered by Neutron Irradiation with an Applied Magnetic Field". Journal of Applied Physics. 39 (2): 989–990. doi:10.1063/1.1656361. ISSN 0021-8979.
  12. ^ a b c Woodgate, Christopher D.; Patrick, Christopher E.; Lewis, Laura H.; Staunton, Julie B. (2023-10-28). "Revisiting Néel 60 years on: The magnetic anisotropy of L10 FeNi (tetrataenite)". Journal of Applied Physics. 134 (16). arXiv:2307.15470. doi:10.1063/5.0169752. ISSN 0021-8979.
  13. ^ a b Lewis, L. H. (January 27, 2014). "Inspired by nature: investigating tetrataenite for permanent magnet applications". Journal of Physics: Condensed Matter. 26 (6). IOP Publishing: 064213. doi:10.1088/0953-8984/26/6/064213. PMID 24469336. S2CID 24710267.
  14. ^ a b c d e Nayak, Bibhuranjan (January 1, 2015). "Tetrataenite in terrestrial rock". American Mineralogist. 100 (1): 209–214. Bibcode:2015AmMin.100..209N. doi:10.2138/am-2015-5061. S2CID 128688369.
  15. ^ Barthelmy, Dave. "Tetrataenite Mineral Data". webmineral.com. Retrieved 2018-04-10.
  16. ^ a b "Taenite." Britannica Academic, Encyclopædia Britannica, 6 Nov. 2009. academic-eb-com.ezproxy.neu.edu/levels/collegiate/article/taenite/342903. Accessed 30 Mar. 2018.
  17. ^ a b Lewis, Laura H.; Stamenov, Plamen S. (2023-12-10). "Accelerating Nature: Induced Atomic Order in Equiatomic FeNi". Advanced Science. 11 (7). doi:10.1002/advs.202302696. ISSN 2198-3844. PMC 10870030. PMID 38072671.
  18. ^ Ivanov, Yurii P.; Sarac, Baran; Ketov, Sergey V.; Eckert, Jürgen; Greer, A. Lindsay (2022). "Direct Formation of Hard-Magnetic Tetrataenite in Bulk Alloy Castings". Advanced Science. 10 (1): e2204315. doi:10.1002/advs.202204315. PMC 9811435. PMID 36281692. S2CID 253108234.
  19. ^ Ivanov, Yurii P.; Sarac, Baran; Ketov, Sergey V.; Eckert, Jürgen; Greer, A. Lindsay (2022-10-25). "Direct Formation of Hard‐Magnetic Tetrataenite in Bulk Alloy Castings". Advanced Science. 10 (1): 2204315. doi:10.1002/advs.202204315. ISSN 2198-3844. PMC 9811435. PMID 36281692. S2CID 253108234.
  20. ^ "Method of tetratenite production and system therefor".
  21. ^ Paddy Hirsch (8 November 2022). "They made a material that doesn't exist on Earth. That's only the start of the story". NPR. Retrieved 1 April 2023.
  22. ^ a b Dos Santos, E. (6 September 2014). "Kinetics of tetrataenite disordering". Journal of Magnetism and Magnetic Materials. 375: 234–241. doi:10.1016/j.jmmm.2014.09.051.
  23. ^ Einsle, Joshua F.; Eggeman, Alexander S.; Martineau, Ben H.; Saghi, Zineb; Collins, Sean M.; Blukis, Roberts; Bagot, Paul A. J.; Midgley, Paul A.; Harrison, Richard J. (2018-12-04). "Nanomagnetic properties of the meteorite cloudy zone". Proceedings of the National Academy of Sciences. 115 (49): E11436–E11445. Bibcode:2018PNAS..11511436E. doi:10.1073/pnas.1809378115. ISSN 0027-8424. PMC 6298078. PMID 30446616.