My research focuses on magnetic nanoparticles that have very uniform sizes, and we study their fundamental behavior, as well as possible applications in data storage media, permanent magnets, and biomedicine. One of the consequences of this monodispersity is that the particles can then self-assemble into arrays (shown below), just as atoms come together to form a crystal. We are investigating the collective behavior of the nanoparticle arrays that are analogous to those in crystals. Isolated iron atoms do not interact with each other and are paramagnetic, but in an iron crystal the interactions lead to ferromagnetism. Superparamagnetic-to-ferromagnetic and insulator-to-metal phase transitions are expected as the nanoparticles are brought closer together. We have also developed a method to replace the surfactant coating the particles with an inorganic matrix, and are exploring methods that exploit this approach to prepare functional nanocomposites.
|Abdelgawad, Ahmed||Graduate Studentfirstname.lastname@example.org|
|Bapna, Mukund||Graduate Studentemail@example.com|
|Matty, Michael||Undergraduate Student|
|Oberdick, Sam||Graduate Studentfirstname.lastname@example.org|
|Parks, Brad||Graduate Studentemail@example.com|
|Piotrowski, Stephan||Graduate Studentfirstname.lastname@example.org|
|Wu, Alicia||Undergraduate Student|
- "TCE Dechlorination Rates, Pathways, and Efficiency of Nanoscale Iron Particles with Different Properties," Yueqiang Liu, Sara A. Majetich, Robert D. Tilton, David S. Sholl, and Gregory V. Lowry, Environ. Sci. Technol. 39, 1338 (2005)
- "Superparamagnetism in carbon-coated Co particles produced by the Kratschmer carbon arc process," M. E. McHenry, S. A. Majetich, J. O. Artman, M. DeGraef, and S. W. Staley, Phys. Rev. B 49, 11358 (1994)
- "Synthesis and Utilization of Monodisperse Superparamagnetic Colloidal Particles for Magnetically Controllable Photonic Crystals," Xiangling Xu, Gary Friedman, Keith D. Humfeld, Sara A. Majetich, and Sanford A. Asher, Chem. Mater. 14, 1249 (2002)
- "Preparation and characterization of monodisperse Fe nanoparticles,"D Farrell, S A Majetich, J P Wilcoxon, Journal of Phys. Chem. B 107, 11022-11030 (2003)
- "Superparamagnetic photonic crystals," Xiangling Xu, Gary Friedman, Keith D Humfeld, Sara A Majetich, Sanford A Asher, Adv. Mater. 13, 1681 (2001)
- "Spin waves across 3-Dimensional, close-packed nanoparticles." Krycka, Kathryn, James J. Rhyne, Samuel D. Oberdick, Ahmed M. Abdelgawad, Julie Borchers, Yumi Ijiri, Sara A. Majetich, and Jeffrey W. Lynn. New Journal of Physics (2018).
- "Spin-Orbit-Torque Switching in 20-nm Perpendicular Magnetic Tunnel Junctions," Mukund Bapna, Brad Parks, Samuel D. Oberdick, Hamid Almasi, Weigang Wang, and Sara A. Majetich, PHYSICAL REVIEW APPLIED 10, 024013 (2018)
- "Spin canting across core/shell Fe3O4/MnxFe3−xO4 nanoparticles," Samuel D. Oberdick, Ahmed Abdelgawad, Carlos Moya, Samaneh Mesbahi-Vasey, Demie Kepaptsoglou, Vlado K. Lazarov, Richard F. L. Evans , Daniel Meilak, Elizabeth Skoropata, Johan van Lierop, Ian Hunt-Isaak, Hillary Pan, Yumi Ijiri, Kathryn L. Krycka, Julie A. Borchers & Sara A. Majetich,Scientific Reports 8, 3425 (2018)
- "Magnetic vortices in nanocaps induced by curvature." Abdelgawad, Ahmed M., Nikhil Nambiar, Mukund Bapna, Hao Chen, and Sara A. Majetich. AIP Advances 8, no. 5 (2018): 056321.
- "Superparamagnetic perpendicular magnetic tunnel junctions for true random number generators," Bradley Parks, Mukund Bapna, Julianne Igbokwe, Hamid Almasi, Weigang Wang, and Sara A. Majetich, AIP ADVANCES 8, 055903 (2018)