Sara Majetich

Department of Physics, Carnegie Mellon University
Ph.D., University of Georgia
Summary:

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.

Students
Namesort descending Position Email
Abdelgawad, Ahmed Graduate Student abdel@cmu.edu
Bapna, Mukund Graduate Student mbapna@cmu.edu
Fan, Farreltin Undergraduate Student
Matty, Michael Undergraduate Student
Oberdick, Sam Graduate Student samoberdick@gmail.com
Parks, Brad Graduate Student bparks@andrew.cmu.edu
Piotrowski, Stephan Graduate Student stephan.piotrowski@gmail.com
Wu, Alicia Undergraduate Student

Ahmed Abdelgawad


Graduate Student

abdel@cmu.edu
5000 Forbes Avenue, Pittsburgh PA, 15213

Affiliation:

Physics
Carnegie Mellon University

Mukund Bapna


Graduate Student

mbapna@cmu.edu
5000 Forbes Avenue, Pittsburgh PA, 15213

Affiliation:

Physics
Carnegie Mellon University

Farreltin Fan


Undergraduate Student


6404 Wean Hall, Pittsburgh PA, 15213

Affiliation:

Physics
Carnegie Mellon University

Michael Matty


Undergraduate Student


6404 Wean Hall, Pittsburgh PA, 15213

Affiliation:

Physics
Carnegie Mellon University

Sam Oberdick


Graduate Student

samoberdick@gmail.com
5000 Forbes Avenue, Pittsburgh PA, 15213

Affiliation:

Physics
Carnegie Mellon University

Brad Parks


Graduate Student

bparks@andrew.cmu.edu
5000 Forbes Avenue, Pittsburgh PA, 15213

Affiliation:

Physics
Carnegie Mellon University

Stephan Piotrowski


Graduate Student

stephan.piotrowski@gmail.com
5000 Forbes Avenue, Pittsburgh PA, 15213

Affiliation:

Physics
Carnegie Mellon University

Alicia Wu


Undergraduate Student


6404 Wean Hall, Pittsburgh PA, 15213

Affiliation:

Physics
Carnegie Mellon University
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. "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)
  4. "Preparation and characterization of monodisperse Fe nanoparticles,"D Farrell, S A Majetich, J P Wilcoxon, Journal of Phys. Chem. B 107, 11022-11030 (2003)
  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. "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. MajetichPHYSICAL REVIEW APPLIED 10, 024013 (2018)
  2. "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)
  3. "Current control of time-averaged magnetization in superparamagnetic tunnel junctions," Mukund Bapna and  Sara A. MajetichAppl. Phys. Lett. 111, 243107 (2017)
  4. "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)
  5. "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)
  6. "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)

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