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High-pressure annealing of a prestructured nanocrystalline precursor to obtain tetragonal and orthorhombic polymorphs of Hf3N4

High-pressure annealing of a prestructured nanocrystalline precursor to obtain tetragonal and orthorhombic polymorphs of Hf3N4
High-pressure annealing of a prestructured nanocrystalline precursor to obtain tetragonal and orthorhombic polymorphs of Hf3N4

Transition metal nitrides containing metal ions in high oxidation states are a significant goal for the discovery of new families of semiconducting materials. Most metal nitride compounds prepared at high temperature and high pressure from the elements have metallic bonding. However amorphous or nanocrystalline compounds can be prepared via metal-organic chemistry routes giving rise to precursors with a high nitrogen:metal ratio. Using X-ray diffraction in parallel with high pressure laser heating in the diamond anvil cell this work highlights the possibility of retaining the composition and structure of a metastable nanocrystalline precursor under high pressure-temperature conditions. Specifically, a nanocrystalline Hf3N4 with a tetragonal defect-fluorite structure can be crystallized under high-P,T conditions. Increasing the pressure and temperature of crystallization leads to the formation of a fully recoverable orthorhombic (defect cottunite-structured) polymorph. This approach identifies a novel class of pathways to the synthesis of new crystalline nitrogen-rich transition metal nitrides.
nitride, x-ray diffraction xrd, hf
1946-4274
1-4
Salamat, Ashkan
5af74416-eb78-4ee4-844c-2499a79951a8
Bouvier, Pierre
6b2e78fa-e40c-4271-addd-3f25488b10f3
Gray, B.
71191ba3-7aa6-4612-aaf9-f24b8b4f1119
Hector, Andrew L.
f19a8f31-b37f-4474-b32a-b7cf05b9f0e5
Kimber, Simon A.J.
568a23f5-7a81-44b3-9afd-42762854722c
McMillan, Paul F.
8bca9219-06e0-4621-bdae-ad059709a147
Salamat, Ashkan
5af74416-eb78-4ee4-844c-2499a79951a8
Bouvier, Pierre
6b2e78fa-e40c-4271-addd-3f25488b10f3
Gray, B.
71191ba3-7aa6-4612-aaf9-f24b8b4f1119
Hector, Andrew L.
f19a8f31-b37f-4474-b32a-b7cf05b9f0e5
Kimber, Simon A.J.
568a23f5-7a81-44b3-9afd-42762854722c
McMillan, Paul F.
8bca9219-06e0-4621-bdae-ad059709a147

Salamat, Ashkan, Bouvier, Pierre, Gray, B., Hector, Andrew L., Kimber, Simon A.J. and McMillan, Paul F. (2014) High-pressure annealing of a prestructured nanocrystalline precursor to obtain tetragonal and orthorhombic polymorphs of Hf3N4. [in special issue: 2013 MRS Fall Meeting - Symposium OO � Solid-State Chemistry of Inorganic Materials] MRS Proceedings, 1655, 1-4. (doi:10.1557/opl.2014.366).

Record type: Article

Abstract


Transition metal nitrides containing metal ions in high oxidation states are a significant goal for the discovery of new families of semiconducting materials. Most metal nitride compounds prepared at high temperature and high pressure from the elements have metallic bonding. However amorphous or nanocrystalline compounds can be prepared via metal-organic chemistry routes giving rise to precursors with a high nitrogen:metal ratio. Using X-ray diffraction in parallel with high pressure laser heating in the diamond anvil cell this work highlights the possibility of retaining the composition and structure of a metastable nanocrystalline precursor under high pressure-temperature conditions. Specifically, a nanocrystalline Hf3N4 with a tetragonal defect-fluorite structure can be crystallized under high-P,T conditions. Increasing the pressure and temperature of crystallization leads to the formation of a fully recoverable orthorhombic (defect cottunite-structured) polymorph. This approach identifies a novel class of pathways to the synthesis of new crystalline nitrogen-rich transition metal nitrides.

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Published date: 2014
Keywords: nitride, x-ray diffraction xrd, hf
Organisations: Electrochemistry

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Local EPrints ID: 366968
URI: http://eprints.soton.ac.uk/id/eprint/366968
ISSN: 1946-4274
PURE UUID: 6889452d-5b25-47ec-88ec-053748f59f3d
ORCID for Andrew L. Hector: ORCID iD orcid.org/0000-0002-9964-2163

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Date deposited: 21 Jul 2014 10:04
Last modified: 15 Mar 2024 02:52

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Contributors

Author: Ashkan Salamat
Author: Pierre Bouvier
Author: B. Gray
Author: Simon A.J. Kimber
Author: Paul F. McMillan

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