Discipline: Nanoscience or Materials Science
Pius Suh - University of the District of Columbia
Co-Author(s): Marzieh Savadkoohi, University of the District of ColumbiaAndrew Grizzle, University of the District of ColumbiaBishnu R. Dahal, Intel corporationChristopher D’Angelo, University of the District of ColumbiaProfessor Pawan Tyagi* University of the District of Columbia
Paramagnetic molecules, with a net spin state, can tailor magnetic exchange coupling between two ferromagnetic (FM) electrodes in magnetic tunnel junction-based molecular spintronics devices (MTJMSD). Magnetic coupling between paramagnetic molecules and two FM electrodes in MTJ-based devices depends on a net molecular spin state. Our prior studies extensively studied the atomic analog of the single molecular magnet, where the whole molecular geometry and internal features were approximated to appear as one atom representing that molecule. To advance the understanding of the impact of internal molecular structure on MTJMSD, we have focused on multi-segmented molecules. This investigation aims to fill the knowledge gap about the role of intramolecular coupling on the magnetic properties of the MTJMSD. This research explored a double-segmented molecule containing two sections, with a net spin state. In this research, we tested the hypothesis that variation in the strength and nature of intra-molecular coupling among multiple segments of a molecule can produce a novel testbed to observe the novel phenomenon. This paper investigates the effect of intra-molecular coupling (Jm) on the MTJMSD magnetic properties using Monte Carlo Simulation (MCS). We varied Jm magnitude and sign and studied its subsequent impact on the MTJMSD magnetic properties at different thermal energies. We also examined the effect of Jm on the MTJMSD evolution under varying Jm. Device magnetization was recorded as a function of time for simulation counts to achieve device stabilization and capture temporal evolution. Our MCS results showed that Jm yielded an impact localized around the junction area at low thermal energy. At increased thermal energy paramagnetic Molecules start losing their magnetic power, hence we observed the entire system was set into chaos with random spin directions. This research sets the foundation for more investigations on the effect of intra-molecular coupling on the magnetic properties of the MTJMSD.
Funder Acknowledgement(s): We gratefully acknowledge the funding support from the National Science Foundation-CREST Award,
Faculty Advisor: Professor Pawan Tyagi, email@example.com
Role: Pius Suh conducted theoretical simulations. Pius Suh, Marzieh, Eva, Bishnu, and Andrew helped with data analysis and graphing of the data. Chris wrote the Monte Carlo simulation code to simulate MTJMSD under the supervision and direction of Pawan. Pius Suh and Professor Pawan Tyagi analyzed the experimental and theoretical data and wrote the manuscript.