Monte Carlo Simulations Investigating the Effect of Intra-Molecular Coupling on the Magnetic Properties of Magnetic Tunnel Junction Based Molecular Spintronics Devices

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 is dependent on a net molecular spin state. However, there is a knowledge gap about the role of the intramolecular coupling on the magnetic properties of the MTJMSD. This research tested the hypothesis that variation in the strength and nature of intra-molecular coupling among multiple segments of a molecule can produce a new testbed to observe the novel phenomenon. Here, we investigated the effect of intramolecular coupling (Jm) on the MTJMSD magnetic properties using Monte Carlo Simulation (MCS). We varied Jm strength and studied its subsequent impact on the MTJMSD magnetic properties at different thermal energies. Device magnetization was recorded as a function of time for various simulation counts to achieve device stabilization and to capture temporal evolution. Our MCS results showed that low Jm yielded an impact localized around the junction area. This behavior creates a platform for more studies on the effect of intra-molecular coupling on the magnetic properties of the MTJMSD.