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An ac susceptibility study in capped Ni/Ni(OH)(2) core-shell nanoassemblies: dual peak observations

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dc.contributor.author Godsell, Jeffrey F.
dc.contributor.author Balla, Tanushree
dc.contributor.author Ryan, Kevin M.
dc.contributor.author Roy, Saibal
dc.date.accessioned 2019-02-26T12:06:31Z
dc.date.available 2019-02-26T12:06:31Z
dc.date.issued 2011
dc.identifier.issn 0022-3727
dc.identifier.uri http://hdl.handle.net/10344/7628
dc.description peer-reviewed en_US
dc.description.abstract In this study, the ac susceptibility (χ' and χ'') variation with temperature (10–100 K) for oleic acid (OA) capped Ni/Ni(OH)2 core–shell nanoparticle assemblies are reported at frequencies varying from 0.1 to 1000 Hz. Nanoparticle assemblies, with two average particle diameters of ~34 nm and ~14 nm, were synthesized using a wet chemical synthesis approach. Two peaks in the ac susceptibility versus temperature curves are clearly discernable for each of the samples. The first, occurring at ~22 K was attributed to the paramagnetic/antiferromagnetic transition of the Ni(OH)2 present in the shell. The second higher temperature peak was attributed to the superparamagnetic blocking of the pure Ni situated at the core of the nanoparticles. The higher temperature peaks in both the χ' and χ'' curves were observed to increase with increasing frequency. Thus the Néel and the blocking temperatures for such core–shell nanoassemblies were clearly identified from the ac analysis, whereas they were not discernible (superimposed) even from very low dc (FC/ZFC) field measurements. Interparticle interactions within the assemblies were studied through the fitting of phenomenological laws to the experimental datasets. It is observed that even with an OA capping layer, larger Ni/Ni(OH)2 nanoparticles experience a greater degree of sub-capping layer oxidation thus producing lower magnetic interaction strengths. en_US
dc.language.iso eng en_US
dc.publisher IOP Publishing en_US
dc.relation info:eu-repo/grantAgreement/EC/FP7/257375 en_US
dc.relation.ispartofseries Journal of Physics D: Applied Physics;44 (32),
dc.relation.uri https://iopscience.iop.org/article/10.1088/0022-3727/44/32/325004/meta
dc.rights This is the author version of "An ac susceptibility study in capped Ni/Ni(OH)(2) core-shell nanoassemblies: dual peak observations" which was published in the Journal of Physics D: Applied Physics. The final publshed version is available at https://iopscience.iop.org/article/10.1088/0022-3727/44/32/325004/meta en_US
dc.subject magnetic-properties en_US
dc.subject nanocrystals en_US
dc.subject particles en_US
dc.subject dynamics en_US
dc.title An ac susceptibility study in capped Ni/Ni(OH)(2) core-shell nanoassemblies: dual peak observations en_US
dc.type info:eu-repo/semantics/article en_US
dc.type.supercollection all_ul_research en_US
dc.type.supercollection ul_published_reviewed en_US
dc.date.updated 2019-02-26T11:56:52Z
dc.identifier.doi 10.1088/0022-3727/44/32/325004/meta
dc.contributor.sponsor SFI en_US
dc.contributor.sponsor ERC en_US
dc.relation.projectid 06/IN.1.I98 en_US
dc.relation.projectid 257375 en_US
dc.relation.projectid 06/IN.1/I85 en_US
dc.rights.accessrights info:eu-repo/semantics/openAccess en_US
dc.internal.rssid 1128349
dc.internal.copyrightchecked Yes
dc.identifier.journaltitle JOURNAL OF PHYSICS D-APPLIED PHYSICS
dc.description.status peer-reviewed


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