Statistics Seminar Series 2009-10
Title:
Modelling, development and
characterization of novel
Nanocomposite, High-Frequency
Magnetic Materials for Integrated
Devices
Speaker:
Jeffrey F. Godsell, Tyndall Institute, UCC
Venue and time:
Western Gateway (IT) Building, G09
Mon 3rd March 3-4pm
Abstract:
Package or chip integrated inductors are one of the key requirements to enable the
efficient supply of power to future miniaturised/handheld electronic devices. The passive
magnetic circuit components in integrated devices are inextricably moving towards
increased efficiencies coupled with a need for miniaturisation of the ferromagnetic cores.
While traditional magnetic materials are a well understood, well reported and mature area
of physics/engineering, nano-engineered/structured magnetic materials are receiving
increasing attention due to their potential for the realisation of enhanced magnetic and
structural properties over that of traditional bulk magnetic materials.
In this Science Foundation Ireland Principal Investigator (SFI-PI) project a
number of both 2-dimensional and 3-dimensional nanostructures are being synthesised
and analyzed with a view to creating materials with improved soft magnetic properties. 2dimensional magnetic thin films studied include electroplated CoP/CoPRe multilayered
structures. These structures are electroplated using a waveform modulated plating
technique to produce laminations of alternating phosphorous rich and phosphorous
deficient multi-nanolayered phase films. Additionally, 3-dimensional structures based on
nanocomposite mesoporous silica structures have been synthesised and reported.
Nanoparticle doped silica spheres and nanoparticle impregnated mesoporous silica
templates have been synthesised using a facile sol-gel as well as a microwave synthesis
method. Thus prepared nanostructured materials are being incorporated as high frequency
soft magnetic cores in a MEMS type of technique inside batch fabricated microtransformers and micro-inductors on silicon.
Interesting magnetic properties in 3D nanostructures have been attributed to
nanoparticle surface effects coupled with varying degrees of magnetic interactions. An
analysis of the high frequency permeability spectrum for electroplated Ni45Fe55 2D thin
films has also been carried out to quantitatively analyse the material’s high frequency
performance. Material parameters were determined by fitting a combined LLG and eddy
current model to the measured spectrum. Complex permeability spectra of the films were
investigated at frequencies up to 9 GHz to identify both the film’s spectroscopic splitting
factor (g) and its effective dimensionless damping parameter (α). Ferromagnetic
resonance frequencies ranging from 4.3 to 5.7 GHz have been analysed by studying both
the zero crossing frequency of the real part of the complex permeability spectra (μr′) and
the peak resonance frequency of the imaginary part of the spectra.
*Contact: jeffrey.godsell@tyndall.ie
Joint work with:
Keith P. Doneganb, Dave Otwayb, Justin Holmesb, Michael Morrisb, Paul McCloskeya,
Terence O’Donnella, Saibal Roya
a
Tyndall National Institute, University College Cork, Ireland.
b
Chemistry Department, University College Cork, Ireland.