Nanomagnetic properties of the meteorite cloudy zone

Meteorites contain a record of their thermal and magnetic history, written in the intergrowths of iron-rich and nickel-rich phases that formed during slow cooling. Of intense interest from a magnetic perspective is the "cloudy zone," a nanoscale intergrowth containing tetrataenite-a natura...

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Main Authors: Einsle, J, Eggeman, A, Martineau, B, Saghi, Z, Collins, S, Blukis, R, Bagot, P, Midgley, P, Harrison, R
Format: Journal article
Language:English
Published: National Academy of Sciences 2018
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author Einsle, J
Eggeman, A
Martineau, B
Saghi, Z
Collins, S
Blukis, R
Bagot, P
Midgley, P
Harrison, R
author_facet Einsle, J
Eggeman, A
Martineau, B
Saghi, Z
Collins, S
Blukis, R
Bagot, P
Midgley, P
Harrison, R
author_sort Einsle, J
collection OXFORD
description Meteorites contain a record of their thermal and magnetic history, written in the intergrowths of iron-rich and nickel-rich phases that formed during slow cooling. Of intense interest from a magnetic perspective is the "cloudy zone," a nanoscale intergrowth containing tetrataenite-a naturally occurring hard ferromagnetic mineral that has potential applications as a sustainable alternative to rare-earth permanent magnets. Here we use a combination of high-resolution electron diffraction, electron tomography, atom probe tomography (APT), and micromagnetic simulations to reveal the 3D architecture of the cloudy zone with subnanometer spatial resolution and model the mechanism of remanence acquisition during slow cooling on the meteorite parent body. Isolated islands of tetrataenite are embedded in a matrix of an ordered superstructure. The islands are arranged in clusters of three crystallographic variants, which control how magnetic information is encoded into the nanostructure. The cloudy zone acquires paleomagnetic remanence via a sequence of magnetic domain state transformations (vortex to two domain to single domain), driven by Fe-Ni ordering at 320 °C. Rather than remanence being recorded at different times at different positions throughout the cloudy zone, each subregion of the cloudy zone records a coherent snapshot of the magnetic field that was present at 320 °C. Only the coarse and intermediate regions of the cloudy zone are found to be suitable for paleomagnetic applications. The fine regions, on the other hand, have properties similar to those of rare-earth permanent magnets, providing potential routes to synthetic tetrataenite-based magnetic materials.
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spelling oxford-uuid:6e5e0cad-f7f4-4fd7-8993-ccb023d5efb92022-03-26T19:24:03ZNanomagnetic properties of the meteorite cloudy zoneJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:6e5e0cad-f7f4-4fd7-8993-ccb023d5efb9EnglishSymplectic Elements at OxfordNational Academy of Sciences2018Einsle, JEggeman, AMartineau, BSaghi, ZCollins, SBlukis, RBagot, PMidgley, PHarrison, RMeteorites contain a record of their thermal and magnetic history, written in the intergrowths of iron-rich and nickel-rich phases that formed during slow cooling. Of intense interest from a magnetic perspective is the "cloudy zone," a nanoscale intergrowth containing tetrataenite-a naturally occurring hard ferromagnetic mineral that has potential applications as a sustainable alternative to rare-earth permanent magnets. Here we use a combination of high-resolution electron diffraction, electron tomography, atom probe tomography (APT), and micromagnetic simulations to reveal the 3D architecture of the cloudy zone with subnanometer spatial resolution and model the mechanism of remanence acquisition during slow cooling on the meteorite parent body. Isolated islands of tetrataenite are embedded in a matrix of an ordered superstructure. The islands are arranged in clusters of three crystallographic variants, which control how magnetic information is encoded into the nanostructure. The cloudy zone acquires paleomagnetic remanence via a sequence of magnetic domain state transformations (vortex to two domain to single domain), driven by Fe-Ni ordering at 320 °C. Rather than remanence being recorded at different times at different positions throughout the cloudy zone, each subregion of the cloudy zone records a coherent snapshot of the magnetic field that was present at 320 °C. Only the coarse and intermediate regions of the cloudy zone are found to be suitable for paleomagnetic applications. The fine regions, on the other hand, have properties similar to those of rare-earth permanent magnets, providing potential routes to synthetic tetrataenite-based magnetic materials.
spellingShingle Einsle, J
Eggeman, A
Martineau, B
Saghi, Z
Collins, S
Blukis, R
Bagot, P
Midgley, P
Harrison, R
Nanomagnetic properties of the meteorite cloudy zone
title Nanomagnetic properties of the meteorite cloudy zone
title_full Nanomagnetic properties of the meteorite cloudy zone
title_fullStr Nanomagnetic properties of the meteorite cloudy zone
title_full_unstemmed Nanomagnetic properties of the meteorite cloudy zone
title_short Nanomagnetic properties of the meteorite cloudy zone
title_sort nanomagnetic properties of the meteorite cloudy zone
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