Determining the effective permeability of a laminated CoZrTaB (CZTB) film, through consideration of demagnetisation effects and eddy-displacement currents

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dc.contributor.authorMurphy, Ruaidhríen
dc.contributor.authorWei, Guannanen
dc.contributor.authorMasood, Ansaren
dc.contributor.authorO’Mathúna, Cianen
dc.contributor.authorPavlovic, Zoranen
dc.contributor.authorMcCloskey, Paulen
dc.contributor.authorO’Driscoll, Séamusen
dc.contributor.funderEnterprise Irelanden
dc.contributor.funderHorizon 2020en
dc.date.accessioned2024-12-03T11:53:51Z
dc.date.available2024-12-03T11:53:51Z
dc.date.issued2024-11-08en
dc.description.abstractMulti-laminated thin film inductors are a key emerging technology to enable highly integrated, on-chip, voltage regulators. The permeability of a magnetic core at high frequency is a key determiner of inductance density. In this paper, a multi-lamination magnetic core made up of alternate CZTB amorphous, uniaxially anisotropic magnetic films and AlN dielectric layers is investigated. The individual films are approximately 200 nm thick, appropriate for operation at over 100 MHz, but the laminated structure and overall thickness of several micrometres mean that analytical methods are impractical for computing demagnetisation. Magnetostatic Finite Element Analysis (FEA) is used to model the magnetic core demagnetisation, accounting for various length/width dimensions, magnetic film thicknesses and dielectric thicknesses. At higher frequencies, the dielectric layers, which are included in the structure to suppress induced eddy-currents allow displacement currents to flow through the dielectric layers and lead to increased eddy currents circulating around the overall core structure and thus further increasing loss and reducing permeability. Eddy-current FEA simulations which include the displacement currents, and an analytically derived Equivalent Circuit Model (ECM) are used to model the real and imaginary (loss) components of permeability spectra. The work, therefore determines the combined contributions of both demagnetisation effects and eddy-displacement currents to the reductions in real permeability and the increase in loss components for thicker multi-laminated magnetic cores. Permeameter measurements on fabricated cores, having ten laminations, and with various AlN thicknesses (10, 20, 40 and 60 nm) gave excellent agreement with the predicted effective permeability through the approach of combining the FEA and ECM models, over the 10 MHz to 1 GHz frequency range. It was shown, that at 100 MHz, for multi-laminated cores with thin or higher k dielectric layers, that displacement-eddy currents are dominant, giving a power loss an order of magnitude higher than would be for magnetically induced eddy currents alone.en
dc.description.sponsorshipEnterprise Ireland (IP/2016/0479)en
dc.description.statusPeer revieweden
dc.description.versionAccepted Versionen
dc.format.mimetypeapplication/pdfen
dc.identifier.citationMurphy, R., Wei, G., Masood, A., O’Mathúna, C., Pavlovic, Z., McCloskey, P. and O’Driscoll, S. (2024) 'Determining the effective permeability of a laminated CoZrTaB (CZTB) film, through consideration of demagnetisation effects and eddy-displacement currents', IEEE Transactions on Magnetics. https://doi.org/10.1109/TMAG.2024.3494675en
dc.identifier.doihttps://doi.org/10.1109/TMAG.2024.3494675en
dc.identifier.eissn1941-0069en
dc.identifier.issn0018-9464en
dc.identifier.journaltitleIEEE Transactions on Magneticsen
dc.identifier.urihttps://hdl.handle.net/10468/16698
dc.language.isoenen
dc.publisherInstitute of Electrical and Electronics Engineers (IEEE)en
dc.relation.ispartofIEEE Transactions on Magneticsen
dc.relation.projectinfo:eu-repo/grantAgreement/EC/H2020::RIA/721107/EU/GaN densily integrated with Si-CMOS for reliable, cost effective high frequency power delivery systems/GaNonCMOSen
dc.rights© 2024, IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.en
dc.subjectThin-film magneticen
dc.subjectCZTBen
dc.subjectMulti-laminateden
dc.subjectAlNen
dc.subjectDielectric layeren
dc.subjectDisplacement-eddyen
dc.subjectDemagnetisationen
dc.subjectEffective permeabilityen
dc.subjectInductor-on-siliconen
dc.subjectMagnetic skin effecten
dc.subjectIntegrated voltage regulatoren
dc.titleDetermining the effective permeability of a laminated CoZrTaB (CZTB) film, through consideration of demagnetisation effects and eddy-displacement currentsen
dc.typeArticle (peer-reviewed)en
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