Sara Majetich

Professor, Physics

Bio

Sara Majetich is a Professor of Physics in the Mellon College of Science. Her 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.

Education

• PhD: University of Georgia (1987)
• M.A.: Columbia University (1980)

Research

Majetich's expertise includes the preparation and measurement of magnetic nanostructures.

Publications

• S. K. Piotrowski et al., Size and voltage dependence of effective anisotropy in sub-100-nm perpendicular magnetic tunnel junctions, Phys. Rev. B 94, 014404 (2016)
• A. Hevroni, M. Bapna, S. Piotrowski, S. A. Majetich, G. Markovich, Tracking the Verwey transition in single magnetite nanocrystals by variable-temperature scanning tunneling microscopy, J. Phys. Chem. Lett. 7, 1661 (2016)
• L. Tryputen et al., Patterning of sub-50 nm perpendicular CoFeB/MgO-based magnetic tunnel junctions, Nanotechnology 27, 185302 (2016)
• A. M. Abdelgawad, S. D. Oberdick, S. A. Majetich, Formation of FePt nanodots by wetting of nanohole substrates, AIP Adv., 6, 056114 (2016)
• M. Bapna, S. K. Piotrowski, S. D. Oberdick, M. Li, C.-L. Chien, S. A. Majetich,  Magnetostatic effects on switching in small magnetic tunnel junctions, Appl. Phys. Lett. 108, 022406 (2016)
• V. K. Sakharov, R. A. Booth, S. A. Majetich, High-frequency permeability of Ni and Co particle assemblies, Journal of Applied Physics 115, 17 (2014) 

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