The intra-molecular coupling within multiple units of paramagnetic molecules can produce various effects on molecular spintronics devices (MSD). This paper focuses on double-segmented molecules as the device element to advance understanding of the Impact of internal molecular structure on magnetic tunnel junction-based MSD (MTJMSD). We performed Monte Carlo simulations (MCS) to fill the knowledge gap about the intramolecular coupling role in the magnetic properties of the MTJMSD. This study explored a double-segmented molecule containing two atomic sections, each with a net spin state interacting via Heisenberg exchange coupling within molecules and with ferromagnetic electrodes at different thermal energies, magnetic fields, and coupling strengths. This study also investigated the effect of magnetic field on the double-segmented molecule-based cross-junction-shaped MTJMSD. We also compared the effect of the magnetic field on the mono and double-segmented molecules when connected to two ferromagnetic electrodes. In the strong coupling regime, the intramolecular coupling and molecule coupling with the two ferromagnetic electrodes dominated the MTJMSD response near the molecular junction area. This study provides insight for evaluating the Impact of molecular nanostructure internal connectedness on the integrated MSD.
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Effect of Intra-Molecular Coupling Within Double Segmented Molecules on Equilibrium Magnetic Properties of Molecular Spintronics Devices
The intra-molecular coupling within multiple units of paramagnetic molecules can produce
various effects on molecular spintronics devices (MSD). The effect of the nature of the strong magnetic coupling between a multi-segmented molecule with two ferromagnetic (FM) electrodes is unexplored. Such knowledge is of critical importance for magnetic tunnel junction-based molecular spintronics devices (MTJMSD). MTJMSD architecture experimentally allows very strong bonding between complex molecules and ferromagnetic electrodes. In our prior studies, we have extensively studied the atomic analog of the single molecular magnet. That means 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 research aims to fill the knowledge gap about the intramolecular coupling role in the magnetic properties of the MTJMSD. This study explored a double-segmented molecule containing two atomic sections, each with a net spin state and interacting via Heisenberg exchange coupling within molecules and with ferromagnetic electrodes. The effect of thermal energy was explored on the impact of
intra-molecular coupling on the MTJMSD Heisenberg model. We performed Monte Carlo
simulations(MCS) to study various possibilities in the strong molecule-ferromagnet coupling regime. This research provides insights into the influence of complex molecules on MSD that can be employed in futuristic computers and novel magnetic meta-materials.
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- Award ID(s):
- 1914751
- PAR ID:
- 10333048
- Date Published:
- Journal Name:
- EMC-2022, Columbus, OH
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Paramagnetic single-molecule magnets (SMMs) interacting with the ferromagnetic electrodes of a magnetic tunnel junction (MTJ) produce a new system. The properties and future scope of new systems differ dramatically from the properties of isolated molecules and ferromagnets. However, it is unknown how far deep in the ferromagnetic electrode the impact of the paramagnetic molecule and ferromagnet interactions can travel for various levels of molecular spin states. Our prior experimental studies showed two types of paramagnetic SMMs, the hexanuclear Mn 6 and octanuclear Fe–Ni molecular complexes, covalently bonded to ferromagnets produced unprecedented strong antiferromagnetic coupling between two ferromagnets at room temperature leading to a number of intriguing observations (P. Tyagi, et al. , Org. Electron. , 2019, 64 , 188–194. P. Tyagi, et al. , RSC Adv. , 2020, 10 , (22), 13006–13015). This paper reports a Monte Carlo Simulations (MCS) study focusing on the impact of the molecular spin state on a cross junction shaped MTJ based molecular spintronics device (MTJMSD). Our MCS study focused on the Heisenberg model of MTJMSD and investigated the impact of various molecular coupling strengths, thermal energy, and molecular spin states. To gauge the impact of the molecular spin state on the region of ferromagnetic electrodes, we examined the spatial distribution of molecule-ferromagnet correlated phases. Our MCS study shows that under a strong coupling regime, the molecular spin state should be ∼30% of the ferromagnetic electrode's atomic spins to create long-range correlated phases.more » « less
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