Functional magnetic nanostructures for electromagnetic and biomedical applications

Hari Srikanth Professor of Physics Materials Institute, University of South Florida, Tampa FL, USA

Magnetic nanoparticles are considered fundamental building blocks for spintronic devices. Surface functionalization and shape anisotropy of nanoparticles are key factors that need to be precisely controlled. Dispersion of ferrite nanoparticles into a polymer matrix creates a new class of low-cost, lightweight nanocomposite materials with enhanced and tunable microwave properties for use in high-performance RF and microwave devices, such as integrated high-Q inductors and filters.A challenging issue in polymer nanocomposites is particle agglomeration into non-uniform clusters during the processing stages of thick films. Our experiments over the years have led to overcoming this limitation through surface functionalization. We have also fabricated high-aspect ratio magnetic nanotubes with excellent tunable microwave properties. For nanomedicine and biosensing applications, a combination of these functionalized hybrid nanoparticles with giant magnetoimpedance (GMI) based sensing elements offer a promising approach for highly sensitive detection of cancer cells and biomolecules. Strategies that go beyond simple spherical structures such as core-shell nanoparticle, nanowire, nanotube geometries can be exploited to increase saturation magnetization and heating efficiency in magnetic hyperthermia treatment of cancer cells. Overall I will discuss the role of advanced functional magnetic nanostructures in emerging electromagnetic and biomedical applications.

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[su_row][su_column size="1/3"][/su_column] [su_column size="2/3"]Hari Srikanth, Ph.D. Professor of Physics Director – Functional Materials Laboratory Associate Editor –Journal of Applied Physics Fellow –American Physical Society University of South Florida Department of Physics, ISA2019 4202 E. Fowler Ave TAMPA, FL 33620 E-mail: sharihar@usf.edu Phone: (813)974-2467; Fax: (813)974-5813[/su_column][/su_row] Hari Srikanth is a Professor of Physics at the University of South Florida in Tampa, FL. He received his Ph.D. in experimental condensed matter physics from the Indian Institute of Science (Bangalore) in 1994. After postdoctoral research at Northeastern University in Boston and a research faculty appointment at the University of New Orleans, Hari joined the University of South Florida in 2000 as an Assistant Professor and established the Functional Materials Laboratory. He was tenured and promoted as Associate Professor in 2004 and became a Full Professor in 2009. Hari’s research spans a wide range of topics in the area of magnetism and magnetic materials. Current research focus in his group include investigating magnetization dynamics in nanostructures, exchange bias, magnetic refrigerant materials, giant magneto-impedance (GMI), microwave materials, complex oxides with competing magnetic phases, spin caloric effects and applications of magnetic nanoparticles in nanomedicine. He has over 200 journal publications and holds 2 patents and has given over 100 invited talks and mini-courses around the world. Hari is a Fellow of the American Physical Society, Fellow of Institute of Nanotechnology and a senior member of IEEE. He is also an Associate Editor for Journal of Applied Physics. Hari has been associated with the Magnetism and Magnetic Materials (MMM) conferences for several years as a program and steering committee member, publication editor and publication chair. He has organized topical symposia for professional conferences such as the MRS, APS and other international meetings. His research program over the years has received funding from the US Department of Energy, National Science Foundation and the Army Research Office. Selected recent publications on magnetic nanostructures: 1. “Enhanced magnetism in highly ordered magnetite nanoparticle-filled nanohole arrays” –B. Duong, H. Khurshid, P. Gangopadhyay, J. Devkota, K. Stojak, H. Srikanth, L. Tetard, R. A. Norwood, N. Peyghambarian, M. H. Phan and J. Thomas, Small 10, 2840 (2014) 2. “Tuning exchange bias in Fe/γ-Fe2O3 core-shell nanoparticles: Impacts of interface and surface spins” –H. Khurshid, M. H. Phan, P. Mukherjee and H. Srikanth, Applied Physics Letters 104, 072407 (2014) 3. “Exchange bias effect in Au-Fe3O4 nanocomposites” –S. Chandra, N. A. Frey Huls, M. H. Phan, S. Srinath, M. A. Garcia, Youngmin Lee, Chao Wang, Shouheng Sun, O. Iglesias and H. Srikanth, Nanotechnology 25, 055712 (2014) 4. “A highly sensitive magnetic biosensor for detection and quantification of anticancer drugs tagged to superparamagnetic nanoparticles” –J. Devkota, J. Wingo, T. T. T. Mai, X. P. Nguyen, N. T. Huong, P. Mukherjee, H. Srikanth and M. H. Phan, Journal of Applied Physics 115, 17B503 (2014) 5. “Mechanism and controlled growth of shape and size variant core-shell FeO/Fe3O4 nanoparticles” –H. Khurshid, W. Li, S. Chandra, M. H. Phan, G. C. Hadjipanayis, P. Mukherjee and H. Srikanth, Nanoscale 5, 7942 (2013) 6. “Magnetoimpedance biosensor with enhanced sensitivity for highly sensitive detection of Nanomag-D beads” –J. Devkota, A. Ruiz, P. Mukherjee, H. Srikanth and M. H. Phan, IEEE Transactions on Magnetics 49, 4060 (2013) 7. “Inverse magnetocaloric and exchange bias effects in single crystalline LSMO nanowires” – S. Chandra, A. Biswas, S. Datta, B. Ghosh, A. K. Raychaudhuri and H. Srikanth, Nanotechnology 24, 505712 (2013) 8. “Spin dynamics and criteria for onset of exchange bias in superspin glass Fe/γ-Fe2O3 core-shell nanoparticles” –S. Chandra, H. Khurshid, W. F. Li, G. C. Hadjipanayis, M. H. Phan and H. Srikanth, Physical Review B 86, 014426 (2012) 9. “Surface spin disorder and exchange bias in hollow maghemite nanoparticles” –H. Khurshid, W. F. Li, M. H. Phan, P. Mukherjee, G. C. Hadjipanayis and H. Srikanth, Applied Physics Letters 101, 022403 (2012) 10. “Polymer nanocomposites exhibiting magnetically tunable microwave properties” –K. Stojak, S. Pal, H. Srikanth, C. Morales, J. Dewdney, T. Weller and J. Wang, Nanotechnology 22, 135602 (2011)