Exchange bias mediated by interfacial nanoparticles (invited)

A. E. Berkowitz, S. K. Sinha, E. E. Fullerton, David Smith

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

The objective of this study on the iconic exchange-bias bilayer Permalloy/CoO has been to identify those elements of the interfacial microstructure and accompanying magnetic properties that are responsible for the exchange-bias and hysteretic properties of this bilayer. Both epitaxial and polycrystalline samples were examined. X-ray and neutron reflectometry established that there existed an interfacial region, of width ∼1 nm, whose magnetic properties differed from those of Py or CoO. A model was developed for the interfacial microstructure that predicts all the relevant properties of this system; namely; the temperature and Permalloy thickness dependence of the exchange-bias, HEX, and coercivity, HC; the much smaller measured values of HEX from what was nominally expected; the different behavior of HEX and HC in epitaxial and polycrystalline bilayers. A surprising result is that the exchange-bias does not involve direct exchange-coupling between Permalloy and CoO, but rather is mediated by CoFe2O4 nanoparticles in the interfacial region.

Original languageEnglish (US)
Article number172607
JournalJournal of Applied Physics
Volume117
Issue number17
DOIs
StatePublished - May 7 2015

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Permalloys (trademark)
nanoparticles
magnetic properties
microstructure
coercivity
neutrons
x rays
temperature

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Exchange bias mediated by interfacial nanoparticles (invited). / Berkowitz, A. E.; Sinha, S. K.; Fullerton, E. E.; Smith, David.

In: Journal of Applied Physics, Vol. 117, No. 17, 172607, 07.05.2015.

Research output: Contribution to journalArticle

Berkowitz, A. E. ; Sinha, S. K. ; Fullerton, E. E. ; Smith, David. / Exchange bias mediated by interfacial nanoparticles (invited). In: Journal of Applied Physics. 2015 ; Vol. 117, No. 17.
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