The roles of the exchange and dipole couplings on the magnetoresistance for the nanoparticle arrays

Abstract Based on Monte Carlo simulations and resistor network model, the tunneling magnetoresistance (TMR) for the square anisotropic magnetic nanoparticle arrays with the exchange coupling J and dipolar coupling D has been studied. The simulated results reveal that, the coercivity H c increases with decreasing value of D and increasing magnitude of J ; the value of TMR max decreases with enhancing value of J ; for D max decreases with increasing value of D , while in contrast for D >0.1, it increases with increasing value of D . Those behaviours have been interpreted with the competition of the different energies, including the random anisotropy, exchange and dipolar energies.