Natalie A Frey

NSF IGERT Fellow

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Natalie A. Frey Huls

Research Experience

Current Research

I am currently working on several projects which include:

Ph.D. Candidacy Proposal: Surface and Interface Phenomena in Magnetic Nanostructures and Thin Films [pdf]
Deposition of ferroelectric polymer/magnetic nanoparticle composite thin films using spin casting. The magnetic nanoparticles are grown in our lab using chemical techniques such as co-precipitation and microemulsion. I plan to investigate the ferroelectric/magnetic coupling between the two phases using a low frequency impedance analyzer which I have successfully integrated into our Physical Properties Measurement System (PPMS). This will allow me to take dielectric measurements at a wide range of temperatures (2K<T<300K) and external magnetic fields (0T<H<7T). The resulting films will be evaluated for use in biosensing applications.
The dielectric measurements are also being performed on other ferroelectric/ferromagnetic systems such as BaM/BSTO multilayers and CrO₂/Cr₂O₃ bilayers.
Synthesis and functionalization of composite and core/shell magnetic nanoparticles for biological applications such as targeted drug delivery, MRI contrast enhancement and hyperthermia.
Investigation of magnetic anisotropy in magnetic nanostructures. This is accomplished by measuring the transverse susceptibility over a wide range in field and temperature using a novel RF resonant technique based on a tunnel-diode oscillator.

Past Research

Master's Thesis (fall 2004): Microstructure and Magnetism in Ferrite-Ferroelectric Multilayer Thin Films

Work involved in my thesis included:

Growth of Barium Strontium Titanate (Ba_0.5Sr_0.5TiO₃ or BSTO)/Barium Hexaferrite (BaFe₁₂O₁₉ or BaM) multilayer thin films using magnetron sputtering facilities at Oak Ridge National Laboratory and the University of Central Florida. Control samples of BSTO and BaM films were also grown.

Structural characterization of these films including XRD, surface and cross-section SEM images, and AFM images

Magnetic characterization of multilayer films and BaM films to compare magnetic properties.

Deposition of Fe₃O₄ nanoparticles onto TEM grids, Si/SiO₂ substrates and the magnetic multilayers using the Langmuir-Blodgett technique to investigate coupling between magnetic phases.