liu.seSök publikationer i DiVA
Ändra sökning
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Theoretical stability, thin film synthesis and transport properties of the Mon+1GaCn MAX phase
Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.ORCID-id: 0000-0001-5036-2833
Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
Visa övriga samt affilieringar
2015 (Engelska)Ingår i: Physica Status Solidi. Rapid Research Letters, ISSN 1862-6254, E-ISSN 1862-6270, Vol. 9, nr 3, s. 197-201Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The phase stability of Mon +1GaCn has been investigated using ab-initio calculations. The results indicate stability for the Mo2GaC phase only, with a formation enthalpy of 0.4 meV per atom. Subsequent thin film synthesis of Mo2GaC was performed through magnetron sputtering from elemental targets onto Al2O3 [0001], 6H-SiC [0001] and MgO [111] substrates within the temperature range of 500 degrees C and 750 degrees C. High structural quality films were obtained for synthesis on MgO [111] substrates at 590 degrees C. Evaluation of transport properties showed a superconducting behavior with a critical temperature of approximately 7 K, reducing upon the application of an external magnetic field. The results point towards the first superconducting MAX phase in thin film form.

Ort, förlag, år, upplaga, sidor
Wiley-VCH Verlag , 2015. Vol. 9, nr 3, s. 197-201
Nyckelord [en]
superconducting MAX phases; Mo2GaC; ab-initio calculations; magnetron sputtering; thin films
Nationell ämneskategori
Fysik
Identifikatorer
URN: urn:nbn:se:liu:diva-117388DOI: 10.1002/pssr.201409543ISI: 000351674600009OAI: oai:DiVA.org:liu-117388DiVA, id: diva2:807779
Anmärkning

Funding Agencies|European Research Council under European Community/ERC [258509]; Swedish Research Council (VR) [642-2013-8020, 621-2012-4425]; KAW Fellowship program; SSF synergy grant FUNCASE; Icelandic Research Fund

Tillgänglig från: 2015-04-24 Skapad: 2015-04-24 Senast uppdaterad: 2018-05-24
Ingår i avhandling
1. Synthesis and characterization of Mo-based nanolaminates
Öppna denna publikation i ny flik eller fönster >>Synthesis and characterization of Mo-based nanolaminates
2015 (Engelska)Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

Mn+1AXn (MAX) phases are nanolaminated compounds based on a transition metal (M), a group A element (A), and carbon or/and nitrogen (X), which exhibit a unique combination of ceramic and metallic properties. Mo-based MAX phases are among the least studied, despite indication of superconducting properties and high potential for fabrication of the grapheneanalogous 2D counterpart, Mo2C MXene. Furthermore, incorporation of Mn atoms in these MAX phases may induce a magnetic response.

In this work, I have performed theoretical calculations focused on evaluation of phase stability of the Mon+1GaCn MAX phases, and have synthesized the predicted stable Mo2GaC in thin film form using magnetron sputtering. Close to phase pure epitaxial films were grown at ~590 ºC, and electrical resistivity measurements using a four point probe technique suggest a superconducting behavior with a critical temperature of ~7 K.

The A-layer in the MAX phase can be selectively etched using different types of acids, leading to exfoliation of the MX-layers and realization of MXenes. After synthesis of the MAX phase related material Mo2Ga2C, the previously non-explored Mo2C MXene could be fabricated from etching Mo2Ga2C thin films in 50% hydrofluoric acid at a temperature of ~50 ºC for a duration of ~3 h.

Motivated by the realization of laminated Mo-based materials in 3D as well as 2D, I set out to explore the magnetic properties resulting from Mn-alloying of the non-magnetic Mo2GaC phase. For that purpose, (Mo,Mn)2GaC was synthesized using a DC magnetron sputtering system with Ga and C as elemental targets and a 1:1 atomic ratio Mo:Mn compound target. Heteroepitaxial films on MgO(111) substrates were grown at ~530 ºC, as confirmed by X-ray diffraction. Compositional analysis using energy dispersive X-ray spectroscopy showed a 2:1 ratio of the M and A elements and a 1:1 ratio for the Mo and Mn atoms in the film. Vibrating sample magnetometry was utilized in order to measure the magnetic behavior of the films, showing a magnetic response up to at least 300 K, and with a coercive field of 0.06 T, which is the highest reported for any MAX phase to date.

Ort, förlag, år, upplaga, sidor
Linköping: Linköping University Electronic Press, 2015. s. 37
Serie
Linköping Studies in Science and Technology. Thesis, ISSN 0280-7971 ; 1729
Nationell ämneskategori
Fysik Fysikalisk kemi
Identifikatorer
urn:nbn:se:liu:diva-121262 (URN)978-91-7685-948-3 (ISBN)
Presentation
2015-10-09, Planck, Fysikhuset, Campus Valla, Linköpings universitet, Linköping, 10:15 (Engelska)
Opponent
Handledare
Anmärkning

The series name Linköping Studies in Science and Technology Licentiate Thesis is incorrect. The correct series name is Linköping Studies in Science and Technology Thesis.

Tillgänglig från: 2015-09-11 Skapad: 2015-09-10 Senast uppdaterad: 2019-11-18Bibliografiskt granskad
2. Synthesis and characterization of Mo- and W-based atomic laminates
Öppna denna publikation i ny flik eller fönster >>Synthesis and characterization of Mo- and W-based atomic laminates
2018 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

Mn+1AXn (MAX) phases are inherently nanolaminated compounds based on transition metals (M), A group elements (A), and carbon or/and nitrogen (X), which exhibit a unique combination of ceramic and metallic properties. My thesis work has focused on exploring novel MAX phase chemistries, including elemental combinations beyond those traditionally used for MAX phases, and their graphene-analogous 2D counterpart, MXenes.  

The first part of the thesis investigates Mo-based MAX phases, which are among the least studied, despite indication of superconducting properties and potential for derivation of Mo-based MXenes. Initially, I performed theoretical calculations focused on evaluation of phase stability of the Mon+1GaCn MAX phases, and synthesized the predicted stable Mo2GaC in thin film form using DC magnetron sputtering. Close to phase pure epitaxial films were grown at ~590 °C, and electrical resistivity measurements using a four-point probe technique suggest a superconducting behavior with a critical temperature of ~7 K. The follow-up of this work, was synthesis of a new MAX related material, Mo2Ga2C, also by means of DC magnetron sputtering. The theoretical predictions as well as the materials characterization by X-ray diffraction and neutron powder diffraction, suggested a Ga bilayer interleaved between a set of Mo2C blocks, arranged in a simple hexagonal structure.   

It is known that selectively etching of the A-layer in a MAX phase, shown for A=Al, can lead to realization of a MXene. Hence, the next step in my research was to explore the possibility of etching of A=Ga in Mo2GaC as well as in Mo2Ga2C, targeting a Mo2C MXene, as motivated by theoretically proposed superior thermoelectric properties of this 2D material. While Mo2GaC did not allow removal of the A-layer, I showed that Mo2C MXene could be realized from etching Mo2Ga2C thin films, removing the Ga bilayer, in 50% hydrofluoric acid at a temperature of ~50 °C for a duration of ~3 h. Hence, the results did not only produce the first Mo-based MXene, it also showed that MXenes can be obtained for etching A-elements other than Al. This, in turn, increase the pathways for expanding the family of MXenes.    

I thereafter set out to explore the magnetic properties resulting from Mn-alloying of the non-magnetic Mo2GaC MAX phase. For that purpose, (Mo,Mn)2GaC was synthesized using a  DC magnetron sputtering system with Ga and C as elemental targets and a 1:1 atomic ratio  Mo:Mn compound target. Heteroepitaxial films on MgO(111) substrates were grown at  ~530 °C, as confirmed by X-ray diffraction. Compositional analysis using energy dispersive X-ray spectroscopy showed a 2:1 ratio of the M- and A-elements and a 1:1 ratio for the Mo and Mn atoms in the film. Vibrating sample magnetometry was utilized to measure the magnetic behavior of the films, showing a magnetic response up to at least 300 K, and with a coercive field of 0.06 T, which is the highest reported for any MAX phase to date.  

The second part of my research has been dedicated to realizing new MAX phase related, chemically ordered compounds and their MXene derivatives, and to initiate exploration of their properties. Materials synthesis was performed by pressureless bulk sintering, and inspired by theoretical calculations we showed evidence for a new so called o-MAX phase, Mo2ScAlC2, with an out-of-plane chemically ordered structure. It is the first experimentally verified Sc-containing MAX phase, which makes its corresponding MXene, Mo2ScC2, also presented in this work, the first MXene including Sc. Moreover, I discovered two so called i-MAX phases including W, (W2/3Sc1/3)2AlC and (W2/3Y1/3)2AlC, which display in-plane chemical ordering in the M-layer. Furthermore, both was shown to allow synthesis of their corresponding 2D counterpart; W1.33C MXene, with ordered vacancies.  Initial test on these novel MXenes showed a high potential for hydrogen evolution reaction.  

Altogether, I have in my thesis work realized 6 novel MAX phases and related materials, and have shown evidence for 4 new MXenes. These materials inspire a wide range of future studies, with respect to fundamental properties as well as potential for future applications.   

Ort, förlag, år, upplaga, sidor
Linköping: Linköping University Electronic Press, 2018. s. 59
Serie
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1933
Nationell ämneskategori
Den kondenserade materiens fysik Nanoteknik
Identifikatorer
urn:nbn:se:liu:diva-148012 (URN)10.3384/diss.diva-148012 (DOI)9789176853122 (ISBN)
Disputation
2018-06-11, Planck, Fysikhuset, Campus Valla, Linköping, 10:15 (Engelska)
Opponent
Handledare
Tillgänglig från: 2018-05-24 Skapad: 2018-05-24 Senast uppdaterad: 2019-09-30Bibliografiskt granskad

Open Access i DiVA

fulltext(667 kB)406 nedladdningar
Filinformation
Filnamn FULLTEXT01.pdfFilstorlek 667 kBChecksumma SHA-512
9b079bc0a77d40d3af27a02699e102c66f102216e2cc3124ebc47ed03b87b4525b3bd77457007a33b8ef1a42ccf146419cc91b87e68d5b86ff684fbe71e7a7f5
Typ fulltextMimetyp application/pdf

Övriga länkar

Förlagets fulltext

Personposter BETA

Meshkian, RaheleSigurdur Ingason, ArniDahlqvist, MartinPetruhins, AndrejsLu, JunRosén, Johanna

Sök vidare i DiVA

Av författaren/redaktören
Meshkian, RaheleSigurdur Ingason, ArniDahlqvist, MartinPetruhins, AndrejsLu, JunRosén, Johanna
Av organisationen
TunnfilmsfysikTekniska högskolan
I samma tidskrift
Physica Status Solidi. Rapid Research Letters
Fysik

Sök vidare utanför DiVA

GoogleGoogle Scholar
Totalt: 406 nedladdningar
Antalet nedladdningar är summan av nedladdningar för alla fulltexter. Det kan inkludera t.ex tidigare versioner som nu inte längre är tillgängliga.

doi
urn-nbn

Altmetricpoäng

doi
urn-nbn
Totalt: 517 träffar
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf