Bistable magnetoresistance switching in exchange-coupled CoFe 2O4-Fe3O4 binary nanocrystal superlattices by self-assembly and thermal annealing

Jun Chen, Xingchen Ye, Soong Ju Oh, James M. Kikkawa, Cherie R. Kagan, Christopher B. Murray

Research output: Contribution to journalArticle

53 Citations (Scopus)

Abstract

Self-assembly of multicomponent nanocrystal superlattices provides a modular approach to the design of metamaterials by choosing constituent nanocrystal building blocks with desired physical properties and engineering the interparticle coupling. In this work, we report the self-assembly of binary nanocrystal superlattices composed of magnetically hard CoFe2O 4 nanocrystals and magnetically soft Fe3O4 nanocrystals. Both NaZn13- and MgZn2-type CoFe 2O4-Fe3O4 binary nanocrystal superlattices have been formed by the liquid-air interfacial assembly approach. Exchange coupling is achieved in both types of binary superlattices after thermal annealing under vacuum at 400 C. The exchange-coupled CoFe 2O4-Fe3O4 binary nanocrystal superlattices show single-phase magnetization switching behavior and magnetoresistance switching behavior below 200 K. The NaZn13-type CoFe2O4-Fe3O4 binary nanocrystal superlattices annealed at 500 C even exhibit bistable magnetoresistance switching behavior at room temperature constituting a simple nonvolatile memory function.

Original languageEnglish
Pages (from-to)1478-1486
Number of pages9
JournalACS Nano
Volume7
Issue number2
DOIs
Publication statusPublished - 2013 Feb 26
Externally publishedYes

Keywords

  • binary nanocrystal superlattices
  • BNSLs
  • exchange coupling
  • magnetic nanocrystal
  • magnetoresistance
  • self-assembly

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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