Monte Carlo Simulations Exploring the Impact of Anisotropy on the Equilibrium Properties of Magnetic Tunnel Junction-Based Molecular Spintronics Device

Magnetic tunnel junction molecular-based spintronics device (MTJMSD) may allow the realization of novel magnetic metamaterials and the miniaturization to nanoscale. Our Monte Carlo Simulation (MCS) is designed to study wide range of MTJMSDs that can be realized by combining a large variety of ferromagnetic (FM) electrodes and magnetic molecules. This MCS study represents covalently bonded paramagnetic molecules across the edges of the magnetic tunnel junction (MTJ) with two FMs. We have studied MTJMSDs properties by simulating various material factors such as anisotropy, FM-molecular coupling, thermal energy, etc. Our study focused on understanding the effect of anisotropy of the FM electrodes on the overall MTJMSDs at various temperatures. Our study shows that the multiple domains of opposite spins start to appear on an FM electrode as the anisotropy energy increases. The observation of magnetic domains with starkly different spins were observed around the molecular junction on the FM electrode with high anisotropy. These domains occurred when anisotropy energy was >20% of the Curie energy of the FM electrode. The effect of anisotropy keeps high magnetization of the device close to Curie temperature even when all the coupling effects get nullified due to thermal agitation.