Sara Majetich

Personal | Department
Department of Physics, Carnegie Mellon University
Ph.D., University of Georgia

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.

Most Cited Publications: 
  1. "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)
  2. "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)
  3. "Gold-coated iron nanoparticles for biomedical applications,"M Chen, S Yamamuro, D Farrell, S A Majetich, Journal of Applied Physics 93, 7551 (2003)
  4. "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)
  5. "Superparamagnetic photonic crystals," Xiangling Xu, Gary Friedman, Keith D Humfeld, Sara A Majetich, Sanford A Asher, Adv. Mater. 13, 1681 (2001)
Recent Publications: 
  1. "Current control of time-averaged magnetization in superparamagnetic tunnel junctions," Mukund Bapna and  Sara A. MajetichAppl. Phys. Lett. 111, 243107 (2017)
  2. "Superparamagnetic perpendicular magnetic tunnel junctions for true random number generators," Bradley Parks, Mukund Bapna, Julianne Igbokwe, Hamid Almasi, Weigang Wang, and Sara A. MajetichAIP ADVANCES 8, 055903 (2018)
  3. "Magnetic properties of cube-shaped Fe3O4 nanoparticles in dilute, 2D, and 3D assemblies," C Moya, A M Abdelgawad, N Nambiar and S A MajetichJ. Phys. D: Appl. Phys. 50, 325003 (2017)
  4. "Origin of reduced magnetization and domain formation in small magnetite nanoparticles," Zlatko Nedelkoski, Demie Kepaptsoglou, Leonardo Lari, Tianlong Wen, Ryan A Booth, Samuel D Oberdick, Pedro L Galindo, Quentin M Ramasse, Richard FL Evans, Sara Majetich, Vlado K Lazarov, Sci Rep 7, 45997 (2017)
  5. "Size and voltage dependence of effective anisotropy in sub-100-nm perpendicular magnetic tunnel junctions," Stephan K. Piotrowski, Mukund Bapna, Samuel D. Oberdick, Sara A. Majetich, Mingen Li, C. L. Chien, Rizvi Ahmed, and R. H. Victora, Phys. Rev. B 94, 014404 (2016)

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