Elucidating Magnetic and Spintronic Effects in Open-shell Macromolecules

Open-shell macromolecules are an emerging class of materials, and they have the potential to be implemented in a variety of organic electronic applications.The presence of unpaired electrons endows these materials with properties, such as extremely long spin relaxation times, which are difficult to achieve with common organic semiconductors. In addition to exhibiting weak spin-orbit coupling, these polymers are paramagnetic in nature. This added functionality make these materials suitable for spintronics applications as radicals retain their magnetic moment in solid state electronic devices, thus enabling facile coupling with an external magnetic field. However, the utilization of open-shell macromolecules that could favor spin polarization and spin conservation during transport have never been investigated. Here, we establish the paramagnetic behavior of these molecules at room temperature. We also observe that, at temperatures < 10 K, these materials exhibit weak antiferromagnetic coupling. Additionally, spin transport performance (i.e., giant negative magnetoresistance (i.e., on the order of –100%) of these systems has been demonstrated. These spin-related results suggest that open-shell macromolecules are remarkably potential materials for spintronic applications.