Carnegie Mellon University

Sara Majetich

Sara Majetich

Professor, Physics




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.

More details about current research projects, current group members, and financial support can be found at the Majetich group home page:


  • 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)
  • Samuel D. Oberdick, Sara A. Majetich, Electrophoretic Deposition of Iron Oxide Nanoparticles on TemplatesThe Journal of Physical Chemistry C 117, 18709 (2013)
  • Tianlong Wen, Ryan A. Booth, Sara A. Majetich, Ten-Nanometer Dense Hole Arrays Generated by Nanoparticle LithographyNano Letters 12, 5873 (2012)
  • Tianlong Wen, Sara A. Majetich, Ultra-Large-Area Self-Assembled Monolayers of NanoparticlesACS Nano 5, 8868 (2011)
  • S. A. Majetich, T. Wen, R. A. Booth, Functional Magnetic Nanoparticle Assemblies: Formation, Collective Behavior, and Future DirectionsACS Nano 5, 6081 (2011)
  • Kazuo Yamamoto, Charles R. Hogg, Saeki Yamamuro, Tsukasa Hirayama, Sara A. Majetich, Dipolar ferromagnetic phase transition in Fe3O4 nanoparticle arrays observed by Lorentz microscopy and electron holographyApplied Physics Letters 98, 072509 (2011)
  • JitKang Lim, Caitlin Lanni, Eric R. Evarts, Frederick Lanni, Robert D. Tilton, Sara A. Majetich,Magnetophoresis of NanoparticlesACS Nano 5, 217 (2011)
  • Charles R. Hogg, Sara A. Majetich, James A. Bain, Investigating Pattern Transfer in the Small-Gap Regime Using Electron-Beam Stabilized Nanoparticle Array Etch MasksIEEE Transactions on Magnetics 46, 2307 (2010)
  • K. L. Krycka et al., Core-Shell Magnetic Morphology of Structurally Uniform Magnetite Nanoparticles,Physical Review Letters 104, 207203 (2010)
  • Eric R. Evarts, Limin Cao, David S. Ricketts, Nicholas D. Rizzo, James A. Bain, Sara A. Majetich, Spin transfer torque switching of magnetic tunnel junctions using a conductive atomic force microscope,Applied Physics Letters 95, 132510 (2009)
  • Kazuo Yamamoto, Sara A. Majetich, Martha R. McCartney, Madhur Sachan, Saeki Yamamuro, Tsukasa Hirayama, Direct visualization of dipolar ferromagnetic domain structures in Co nanoparticle monolayers by electron holographyApplied Physics Letters 93, 082502 (2008)
  • M. Sachan, C. Bonnoit, S. A. Majetich, Y. Ijiri, P. O. Mensah-Bonsu, J. A. Borchers, J. J. Rhyne, Field evolution of magnetic correlation lengths in ɛ-Co nanoparticle assembliesApplied Physics Letters 92, 152503 (2008)
  • JitKang Lim, Alexander Eggeman, Frederick Lanni, Robert D. Tilton, Sara A. Majetich, Synthesis and Single-Particle Optical Detection of Low-Polydispersity Plasmonic-Superparamagnetic Nanoparticles,Advanced Materials 20, 1721 (2008)
  • Yueqiang Liu, Sara A. Majetich, Robert D. Tilton, David S. Sholl, Gregory V. Lowry, TCE Dechlorination Rates, Pathways, and Efficiency of Nanoscale Iron Particles with Different PropertiesEnvironmental Science & Technology 39, 1338 (2005)
  • Yi Ding, Sara A. Majetich, Size dependence, nucleation, and phase transformation of FePt nanoparticles,Applied Physics Letters 87, 022508 (2005)