liu.seSearch for publications in DiVA
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Toward Structural Optimization of MAX Phases as Epitaxial Thin Films
Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
2016 (English)In: MATERIALS RESEARCH LETTERS, ISSN 2166-3831, Vol. 4, no 3, p. 152-160Article in journal (Refereed) Published
Abstract [en]

Prompted by the increased focus on MAX phase materials and their two-dimensional counterparts MXenes, a brief review of the current state of affairs in the synthesis of MAX phases as epitaxial thin films is given. Current methods for synthesis are discussed and suggestions are given on how to increase the material quality even further as well as arrive at those conditions faster. Samples were prepared to exemplify the most common issues involved with the synthesis, and through suggested paths for resolving these issues we attain samples of a quality beyond what has previously been reported.

Place, publisher, year, edition, pages
TAYLOR & FRANCIS INC , 2016. Vol. 4, no 3, p. 152-160
Keywords [en]
MAX Phase; Thin Films; Reproducible Materials Synthesis; Sample Quality
National Category
Inorganic Chemistry
Identifiers
URN: urn:nbn:se:liu:diva-132496DOI: 10.1080/21663831.2016.1157525ISI: 000385011000004OAI: oai:DiVA.org:liu-132496DiVA, id: diva2:1046251
Note

Funding Agencies|European Research Council under the European Community Seventh Framework Program (FP7)/ERC Grant [258509]; Swedish Research Council (VR); Knut and Alice Wallenberg (KAW) Fellowship program; SSF synergy grant FUNCASE

Available from: 2016-11-13 Created: 2016-11-12 Last updated: 2018-03-15
In thesis
1. Synthesis and characterization of magnetic nanolaminated carbides
Open this publication in new window or tab >>Synthesis and characterization of magnetic nanolaminated carbides
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

MAX phases are a group of nanolaminated ternary carbides and nitrides, with a composition expressed by the general formula Mn+1AXn (𝑛 = 1 − 3), where M is a transition metal, A is an A-group element, and X is carbon and/or nitrogen. MAX phases have attracted interest due to their unique combination of metallic and ceramic properties, related to their inherently laminated structure of a transition metal carbide (Mn+1Xn) layer interleaved by an A-group metal layer.

This Thesis explores synthesis and characterization of magnetic MAX phases, where the A-group element is gallium (Ga). Due to the low melting point of Ga (T = 30 °C), conventional thin film synthesis methods become challenging, as the material is in liquid form at typical process temperatures. Development of existing methods has therefore been investigated, for reliable/reproducible synthesis routes, including sputtering from a liquid target, and resulting high quality material. Routes for minimizing trial-and-error procedures during optimization of thin film synthesis have also been studied, allowing faster identification of optimal deposition conditions and a simplified transfer of essential deposition parameters between different deposition systems.

A large part of this Thesis is devoted towards synthesis of MAX phase thin films in the Cr-Mn-Ga-C system. First, through process development, thin films of Cr2GaC were deposited by magnetron sputtering. The films were epitaxial, however with small amount of impurity phase Cr3Ga, as confirmed by X-ray diffraction (XRD) measurements. The film structure was confirmed by scanning transmission electron microscopy (STEM) and the composition by energy dispersive X-ray spectroscopy (EDX) inside the TEM.

Inspired by predictive ab initio calculations, the new MAX phase Mn2GaC was successfully synthesized in thin film form by magnetron sputtering. Structural parameters and magnetic properties were analysed. The material was found to have two magnetic transitions in the temperature range 3 K to 750 K, with a first order transition at around 214 K, going from non-collinear antiferromagnetic state at lower temperature to an antiferromagnetic state at higher temperature. The Neél temperature was determined to be 507 K, changing from an antiferromagnetic to a paramagnetic state. Above 800 K, Mn2GaC decomposes. Furthermore, magnetostrictive, magnetoresistive and magnetocaloric properties of the material were iv determined, among which a drastic change in lattice parameters upon the first magnetic transition was observed. This may be of interest for magnetocaloric applications.

Synthesis of both Cr2GaC and Mn2GaC in thin film form opens the possibility to tune the magnetic properties through a solid solution on the transition metal site, by alloying the aforementioned Cr2GaC with Mn, realizing (Cr1-xMnx)2GaC. From a compound target with a Cr:Mn ratio of 1:1, thin films of (Cr0.5Mn0.5)2GaC were synthesized, confirmed by TEM-EDX. Optimized structure was obtained by deposition on MgO substrates at a deposition temperature of 600 ºC. The thin films were phase pure and of high structural quality, allowing magnetic measurements. Using vibrating sample magnetometry (VSM), it was found that (Cr0.5Mn0.5)2GaC has a ferromagnetic component in the temperature range from 30 K to 300 K, with the measured magnetic moment at high field decreasing by increasing temperature. The remanent moment and coercive field is small, 0.036 μB, and 12 mT at 30 K, respectively. Using ferromagnetic resonance spectroscopy, it was also found that the material has pure spin magnetism, as indicated by the determined spectroscopic splitting factor g = 2.00 and a negligible magnetocrystalline anisotropy energy.

Fuelled by the recent discoveries of in-plane chemically ordered quaternary MAX phases, so called i-MAX phases, and guided by ab initio calculations, new members within this family, based on Cr and Mn, were synthesized by pressureless sintering methods, realizing (Cr2/3Sc1/3)2GaC and (Mn2/3Sc1/3)2GaC. Their structural properties were determined. Through these phases, the Mn content is the highest obtained in a bulk MAX phase to date.

This work has further developed synthesis processes for sputtering from liquid material, for an optimized route to achieve thin films of controlled composition and a high structural quality. Furthermore, through this work, Mn has been added as a new element in the family of MAX phase elements. It has also been shown, that alloying with different content of Mn gives rise to varying magnetic properties in MAX phases. As a result of this Thesis, it is expected that the MAX phase family can be further expanded, with more members of new compositions and new properties.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2018. p. 58
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1918
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-145679 (URN)10.3384/diss.diva-145679 (DOI)9789176853429 (ISBN)
Public defence
2018-04-16, Planck, Fysikhuset, Campus Valla, Linköping, 10:15 (English)
Opponent
Supervisors
Available from: 2018-03-15 Created: 2018-03-15 Last updated: 2018-03-22Bibliographically approved

Open Access in DiVA

fulltext(1065 kB)32 downloads
File information
File name FULLTEXT01.pdfFile size 1065 kBChecksum SHA-512
f1f0846404defb07d73f10c80aa44196cea63e358a02e159860771f220a733839672dce74c35f3c3b7917b14e8761236dd442c5e7afe1bf635b0ae2716672cfd
Type fulltextMimetype application/pdf

Other links

Publisher's full text

Search in DiVA

By author/editor
Ingason, Arni SigurdurPetruhins, AndrejsRosén, Johanna
By organisation
Department of Physics, Chemistry and BiologyFaculty of Science & EngineeringThin Film Physics
Inorganic Chemistry

Search outside of DiVA

GoogleGoogle Scholar
Total: 32 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 191 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf