Exchange Coupling in Soft Magnetic Nanostructures and Its Direct Effect on Their Theranostic Properties

Vikas Nandwana, Ruiying Zhou, Jeotikanta Mohapatra, Sungkyu Kim, Pottumarthi V. Prasad, J. P. Liu, Vinayak P. Dravid*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


Exchange coupling between hard and soft magnetic materials at the nanoscale exhibits novel or improved physical properties for energy and data storage applications. Recently, exchange coupling has also been explored in core/shell magnetic nanostructures (MNS) composed of hard and soft magnetic spinel ferrites, but applications have been limited in biomedicine due to the presence of "toxic" cobalt based ferrites as hard magnetic component. We report core/shell MNS where both core and shell components are soft magnetic ferrites (Fe3O4, MnFe2O4, and Zn0.2Mn0.8Fe2O4) and show that exchange coupling still exists due to the difference in their anisotropy. The physical properties (saturation magnetization, susceptibility, anisotropy, r2 relaxivity, and specific absorption rate) of core/shell MNS are compared with the same size single phase counterparts which excludes any size dependent effect and gives the direct effect of exchange coupling. After optimization of core and shell components and their proportions, we have shown that a core/shell MNS shows significantly higher contrast enhancement and thermal activation properties than their single phase counterparts due to exchange coupling between core and shell ferrites. Our finding provides a novel way to improve theranostic properties of spinel ferrite based MNS while maintaining their biocompatibility.

Original languageEnglish (US)
Pages (from-to)27233-27243
Number of pages11
JournalACS Applied Materials and Interfaces
Issue number32
StatePublished - Aug 15 2018


  • contrast enhancement
  • exchange coupling
  • magnetic nanostructures
  • theranostics
  • thermal activation

ASJC Scopus subject areas

  • General Materials Science


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