Monte Carlo simulation of tunneling magnetoresistance in nanostructured materials

A two-level model of tunneling magnetoresistance (MR) containing coplay of the relative orientation of moments between clusters, the intrinsic characters of clusters, and the Coulomb blockade effect, is presented. Based on the Monte Carlo simulation, spin configurations, MR and resistivity as function of temperature and field were studied, respectively. Simulated results are found to be in good agreement with the recent experimental data. The unusual enhancement of MR is attributed to the interaction between the clusters and the intrinsic character of clusters. Although the Coulomb blockade effect plays little role on MR, it has an important effect on the resistivity at low temperature.