Seminar Speaker: Jenny Andrew, University of Florida

Abstract

Nanostructured composite materials have the potential to overcome challenges in many areas of materials research, which cannot be addressed by more conventional single-phase materials. For example, ferroelectric and ferromagnetic materials can be combined to form composites with enhanced multiferroic or exchange coupling properties. Here, we will present multiferroic composite nanomaterials prepared using the electrospinning technique, generating materials with controllable anisotropy and resultant properties. Specifically, Janus-type nanofibers, where two phases are coupled longitudinally, are used to create an anisotropic building block that allows access to both surface and bulk properties of each phase. This novel architecture is linked to an anisotropic interface between the coupled phases, and a model is developed relating fiber composition to interfacial area and resulting functional properties.

Electrospinning results in the formation of fibers that are amorphous and form a continuous fiber network, requiring subsequent processing steps to both crystallize the nanofibers as well as to assemble them into the desired device. By varying the processing conditions, we can tune the diameter and length of the resultant nanowires. The magnetoelectric properties of assembled arrays of BaTiO₃ /CoFe₂O4 nanowires reveal a magnetoelectric coefficient of 514+/- 27 mV cm^-1 Oe^-1 at 1 kHz, considerably larger than bulk values 104 mV cm^-1 Oe^-1.

Assembled arrays of these magnetoelectric nanowires can then be used for a variety of applications and devices. Here, we will present the results of these materials for use as magnetic field and/or current sensors, and antennas. Additionally, we will highlight their potential for biomedical applications where the remote delivery of an electric field is desired, such as in neural tissue engineering.

Speaker Biography

Jennifer Andrew is currently the Margaret A. Ross Professor in the Department of Materials Science & Engineering at the University of Florida. She was awarded the NSF CAREER Award titled “Structure-property Relationships Arising From Interfacial Coupling in Bi-phasic Ceramic Nanocomposites”. Before coming to UF she was a UC President’s Postdoctoral Fellow in Michael J. Sailor’s lab in the Department of Chemistry and Biochemistry at the University of California, San Diego. She received her B.S. in Materials Science from Northwestern University in 2002, and her Ph.D. in Materials Engineering in 2008 from the University of California, Santa Barbara. Her research interests include the development of nanocomposite materials with novel multifunctional electronic and biomedical applications.