IN²UB INTERNATIONAL RESEARCH SEMINARS: “Magnetic Tunnel Junction-based Molecular Spintronics Devices: A Method of Harnessing Exotic Properties of Molecular Nanostructure”






Institut de Nanociència i Nanotecnologia


Aula V11 (Química)

Conferenciant: Dr. Pawan Tyagi, Center for Nanotechnology Research and Education, University of the District of Columbia, Washington DC 20008 USA.

Resum: Molecule-based devices may govern the advancement of logic and memory devices for next-generation computers and may be suitable for quantum computation. Molecules are unparalleled nanostructures to serve as device elements because chemists can mass-produce a variety of molecules with unique optical, magnetic, and transport characteristics. However, the biggest challenge is to connect two or three metal electrodes to the Molecule (s) and develop a robust and versatile device fabrication technology that can be adopted for commercial-scale mass production. Utilizing tunnel junction as a testbed for making molecular devices solve many critical problems [1]. We focused on producing magnetic tunnel junction-based molecular devices (MTJMSD). This talk will show that an MTJMSD evolves when molecules are bridged along the exposed side edges of a tunnel junction. With the MTJMSD approach, many unprecedented advantages become available to devise researchers. MTJMSD enables the connection between ferromagnetic electrodes and a variety of molecules with the spin state. For the first time, the MTJMSD approach enabled magnetic measurements and conventional transport studies[1]. Magnetic studies showed that molecules could transform the magnetic[2] and transport properties of the MTJs[3] at room temperature. Molecules’ strong impact on ferromagnetic electrodes produced several orders resistance changes at room temperature. An MTJMSD approach is a high yield method and can be mass-produced with the conventional microfabrication tools present in typical labs. Our MTJMSD approach also allows numerous control experiments to provide a deep understanding of device mechanisms. This talk will demonstrate two types of control experiments to prove that we successfully made a molecular device. The first control experiment is the reversible impact of making and braking molecular channels on the overall charge transport. We also performed ferromagnetic resonance before and after damaging the tunnel barrier and damaging the molecular channels by using the plasma. In addition, this talk will discuss how the MTJMSD approach is also suitable for making light sensors, biochemical sensors, as molecules are present in the open region.


1. P. Tyagi, “Multilayer edge molecular electronics devices: a review,” J. Mater. Chem., vol. 21, pp. 4733-4742, 2011.

2. P. Tyagi, C. Baker, and C. D’Angelo, “Paramagnetic Molecule Induced Strong Antiferromagnetic Exchange Coupling on a Magnetic Tunnel Junction Based Molecular Spintronics Device,” Nanotechnology, vol. 26, p. 305602, 2015.

3. P. Tyagi and E. Friebe, “Large Resistance Change on Magnetic Tunnel Junction based Molecular Spintronics Devices,” J. Mag. Mag. Mat., vol. 453, pp. 186-192, 2018.,