Impact of Spin Fluctuation on the magnetic properties of Magnetic Tunnel Junction-Based Molecular Spintronic Device (MTJMSD)

Abstract

Striking advancement of science over the last few decades has doubled the need of having faster and more efficient electronic devices. Magnetic tunnel junction-based molecular spintronic devices (MTJMSDs) are potential platforms for futuristic computers and may significantly reduce power consumption and enhance processing speed [1], [2]. Using transport properties of electrons, MTJMSD creates conductive molecular channels between two FM electrodes (FMEs). In our previous work, we investigated the effect of several factors on MTJMSDs' magnetic properties through Monte Carlo Simulation (MCS). Our results showed that i) Molecule-FMEs' coupling strength and nature ii) FMEs' length and thickness and iii) thermal energy have determinative effect on MTJMSD magnetic behavior [3]. For our initial comprehension, we constrained our earlier studies to just electrons' transport properties via molecular channels. In this research we took one step further towards realization of MTJMSD magnetic properties and investigated the effect of spin fluctuation (SF) as well. Here, we report the result of an extreme case where molecules made a strong antiFM coupling with one electrode and a strong FM coupling with another one at room temperature (KT=0.1 of the Curie temperature) for a fixed device size. Our preliminary results show that MTJMSD's need more iteration counts to attain equilibrium state in the presence of SFs. According to our MCS results, 16 molecules can induce antiFM coupling between FMEs in both with and without SF cases. However, the spatial orientation of M is noisier in the presence of SF despite doing 500 million simulation counts. The correlation results agree with spatial orientation of electrodes and molecules' magnetic moment. Based on our observation, there is a strong negative/antiferromagnetic correlation between FMEs when there is no SF. However, there are multiple pockets of average to high negative correlation between FMEs and molecules while applying SF effect. To complement our study and gain a better understanding of the role of SF on MTJMSD's magnetic properties, we will also investigate time evolution of energy, magnetic susceptibility and coupling energy required for transition from low to high magnetization.