uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • 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
The interface and defect structure of superconducting Ba(Fe1-xCox)2As2 thin films
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
Leibniz Institute for Solid State and Materials Research, Dresden. (Institute for Metallic Materials)
Leibniz Institute for Solid State and Materials Research, Dresden. (Institute for Metallic Materials)
Leibniz Institute for Solid State and Materials Research, Dresden. (Institute for Metallic Materials)
Show others and affiliations
2011 (English)In: Microscopy Conference 2011, 28 August – 02 September 2011, Kiel, Germany / [ed] Wolfgang Jäger, 2011Conference paper, Published paper (Refereed)
Abstract [en]

Essential to the understanding of key fundamental properties in the newly discovered iron-based superconductors as well as critically assessing their potential for applications and devices is their fabrication into very high quality thin films.  Thin films of the Ba(Fe1-xCox)2As2 phase – discovered by Sefat et al. [1] and commonly referred to as “Ba-122” – are particularly interesting since this compound appears to be resilient against oxidation and degradation due to water vapor [2], it is considerably easier to deposit compared to other iron-based superconductors, and it has a relatively high critical temperature of 25.5 K. The search for optimal thin film growth parameters is currently the subject of a number of international research groups.  [2 – 11].  However, difficulties overcoming the poor metal/oxide bond at the interface of many substrates has necessitated the need for significant optimization of the deposition parameters [9,10] as well as the use of various intermediate layers [8] to produce well-textured films. In spite of these efforts, nearly all of these films contain an unintentional amorphous or iron-containing layer at the interface. While the nature of this interface is not yet fully understood, the disruption of local crystallographic ordering associated with it precludes the use of these films for interface-sensitive applications such as multilayers or heterostructures where coherent and chemically inert phase boundaries are required.

A detailed investigation into the nature of this interface on both STO and LSAT substrates reveals that it is characterized by the presence of an interdiffusion layer.  Ba diffuses approximately 2 nm into both substrates and is mass-balanced by the previously mentioned amorphous layer of unknown composition (figure 1).  This amorphous layer is rich in iron and, on LSAT, even contains significant amounts of textured iron [9].  The nature of this interface is the first topic of this contribution.

Additionally, the current transport properties of these thin films are observed to be strongly dependent on the type and concentration of defects present.  An overview of the defects observed in this system constitutes the second topic of this contribution.

Finally, it has been shown that, by using a metallic iron buffer layer, a highly coherent and chemically inert interfacial bond can take place [12-14].  The effect of such an interface on the defect landscape and, subsequently, the macroscopic superconducting properties of the Ba-122 thin films will be discussed in detail.

[1] A. Sefat, et al., Phys. Rev. Lett. 101, 117004 (2008)[2] H. Hiramatsu, et al., Phys. Rev. B 80, 052501 (2009)[3] H. Hiramatsu, et al., Appl. Phys. Express 1, 101702 (2008)[4] E. -M. Choi, et al., Appl. Phys. Lett. 95, 062507 (2009)[5] T. Katase, et al., Solid State Commun. 149, 2121 (2009)[6] S. Lee, et al., Appl. Phys. Lett. 95, 212505 (2009)[7] K. Iida, et al., Appl. Phys. Lett. 95, 192501 (2009)[8] S. Lee, et al., Nature Mater. 9, 397 (2010)[9] K. Iida, et al., Phys. Rev. B 81, 100507(R) (2010)[10] T. Katase, et al., Appl. Phys. Lett. 96, 142507 (2010)[11] T. Katase, et al., Appl. Phys. Express 3, 063101 (2010)[12] T. Thersleff, et al., Appl. Phys. Lett. 97, 022506 (2010)[13] K. Iida, et al., Appl. Phys. Lett. 97, 172507 (2010)[14] K. Iida, et al., Appl. Phys. Express 4, 013103 (2011)

Place, publisher, year, edition, pages
2011.
Keyword [en]
superconductivity, interfaces, transmission electron microscopy, defects
National Category
Other Materials Engineering
Research subject
Engineering Science with specialization in Materials Analysis; Physics with spec. in Atomic, Molecular and Condensed Matter Physics
Identifiers
URN: urn:nbn:se:uu:diva-165364OAI: oai:DiVA.org:uu-165364DiVA: diva2:473124
Conference
Microscopy Conference 2011, 28 August – 02 September 2011, Kiel, Germany
Note
Poster presentation at the Microscopy Conference 2011Available from: 2012-01-09 Created: 2012-01-05 Last updated: 2012-01-25Bibliographically approved

Open Access in DiVA

Thersleff_MC2011-Poster(3941 kB)56 downloads
File information
File name FULLTEXT01.pdfFile size 3941 kBChecksum SHA-512
f8829c5623c4abad95f3cc010cb3a674fd3581b46ad30d7e3af0b22175d3c385d0e58ab62c66fa8171c4b6b73958bc9401a49259ffaf86cf650f4d67bb65b81c
Type summaryMimetype application/pdf

Authority records BETA

Thersleff, Thomas

Search in DiVA

By author/editor
Thersleff, Thomas
By organisation
Applied Materials Sciences
Other Materials Engineering

Search outside of DiVA

GoogleGoogle Scholar
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

urn-nbn

Altmetric score

urn-nbn
Total: 808 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • 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