Awards & Honors:
Broadly defined, Dr. Litvinov's research goals are state-of-the-art sustainable interdisciplinary research and education in the rapidly developing field of nano and biomagnetics. The research field encompasses materials, devices, and biological systems that have their functional magnetic building blocks with dimensions on the order of or smaller than the characteristic length, the domain wall thickness, of the constituent magnetic materials. Such single magnetic domain building blocks enable unprecedented functionalities far beyond what is achievable in conventional macroscopic systems.
Among the key endeavors funded by the National Institute of Health, the Alliance for NanoHealth, and National Science Foundation grants, is the creation of a technology that will allow rapid evaluation of the effectiveness of potential antiviral drugs by their ability to block a virus' bond with a cell receptor, among other applications. We use nanomagnetic tags, also referred to as labels, to track biomolecules (proteins, DNAs or RNAs). The tags are magnetic spheres measuring about 50 nanometers – 1,000 times smaller than the width of human hair and are monitored by an array of magnetic-field sensors capable of detecting the presence of these tiny magnetic spheres. These sensors, dubbed giant magnetoresistive (GMR) sensors, are small enough that a million of them can be fit in a single square millimeter of space. Dr. Litvinov's team has succeed in the detection of individual magnetic bead and are in the process of scaling the technology into the nanoscale domain.
Another key research area under development by my team is bit-patterned medium magnetic recording, a project funded by National Science Foundation and Texas Advance Technology Program grants. Dr. Litvinov's team is applying ion beam proximity lithography with a sub-5nm theoretical resolution limit to define the position and shape of data bits on a magnetic disk. This is drastically different from conventional technologies used in today's hard drives, where each data bit is represented by a collection of randomly sized and positioned magnetic crystallites that constitute a magnetic recording layer. Elimination of this randomness promises significant increase in achievable bit density. So far, Dr. Litvinov's team has demonstrated feasibility of patterned medium fabrication using ion beam proximity lithography, significantly contributed to the development of design guidelines for patterned medium read/write systems, investigated feasibility of using high anisotropy magnetic multilayers in bit patterned medium recording.
L. Kaganovsky, D. Litvinov, S. Khizroev, “Investigation of the switching wave propagation in linear chains of magnetic elements,” Journal of Applied Physics 110(4), Art. No. 043901 (2011).
J. Hong, S. Niyogi, E. Bekyarova, M.E. Itkis, P. Ramish, N. Amos, D. Litvinov, C. Berger, W.A. de Heer, S. Khizroev, R.C. Haddon, “Effect of Nitrophenyl Functionalization on the Magnetic Properties of Epitaxial Graphene,” Small, 7(9), 1175–1180, (2011).
G. Leem, Sh. Zhang, A.C. Jamison, E. Galstyan, I. Rusakova, B. Lorenz, D. Litvinov, T.R. Lee, “Light-Induced Covalent Immobilization of Monolayers of Magnetic Nanoparticles on Hydrogen-Terminated Silicon,” ACS Applied Materials and Interfaces 2(10), 2789-2796 (2010).
N. Amos, R. Fernandez, R.M. Ikkawi, M. Shachar, J. Hong, B. Lee, D. Litvinov, S. Khizroev, “Ultrahigh Coercivity Magnetic Force Microscopy Probes to Analyze High-Moment Magnetic Structures and Devices,” IEEE Magnetics Letters 1, 6500104 (1-4) (2010).
D. Smith, L. Chang, J.O. Rantschler, V. Kalatsky, P. Ruchhoeft, S. Khizroev, D. Litvinov, “Size Distribution and Anisotropy Effects on the Switching Field Distribution of Co/Pd Multilayered Nanostructure Arrays,” IEEE Transactions on Magnetics 45(10), 3554-3557 (2009).
Ch. E, J. Rantschler, S. Khizroev, D. Litvinov, “Micromagnetics of Signal Propagation in Magnetic Cellular Logic Data Channels,” Journal of Applied Physics 104, Art. No. 054311, 1-4 (2008).
P. Gomez, D. Litvinov, S. Khizroev, “Calculation of Minimum Parameters Requirements for Low-Field Low-Size Nano Nuclear Magnetic Resonance (NanoNMR),” IEEE Transactions on Magnetics 44 (11), 4464-4467 (2008).
G. Leem, A.C. Jamison, Sh. Zhang, D. Litvinov, T.R. Lee, “Facile Synthesis, Assembly, and Immobilization of Ordered Arrays of Monodisperse magnetic Nanoparticles on Silicon Substrates,” Chemical Communications 40 , 4989-4991 (2008).
J.W. Lau, R.D. McMichael, S.H. Chung, J.O. Rantschler, V. Parekh, D. Litvinov, “Microstructural Origin of Switching Field Distribution in Patterned Co/Pd Multilayer Dots,” Applied Physics Letters 92, Art. No. 012506 (2008).
D. Litvinov, V. Parekh, Ch. E, D. Smith, J. Rantschler, P. Ruchhoeft, D. Weller, S. Khizroev, “Recording Physics, Design Considerations, and Fabrication of Nanoscale Bit-Patterned Media,” IEEE Transactions on Nanotechnology 7(4), 463-476 (2008).
R. Ikkawi, N. Amos, A. Krichevsky, R. Chomko, D. Litvinov, S. Khizroev, “Nanolasers to Enable Storage Densities beyond 10 Tbit/in2,” Applied Physics Letters 91, Art. No. 042502 (2007).
V. Parekh, A. Ruiz, P. Ruchhoeft, S. Brankovic, D. Litvinov, “Close-Packed Noncircular Nanodevice Pattern Generation by Self-Limiting Ion-Mill Process,” Nano Letters 7(10), 3246-3248 (2007).