Effect of Magnetic Field on Giant Magnetoresistance in Antiferromagnetic Film: Computer Simulations

Abstract

The article is aimed at computer modeling of giant magnetic resistance in thin antiferromagnetic films in an external magnetic field. Computer simulation uses the Monte Carlo method and Ising antiferromagnetic model to describe the magnetic properties of the film. Metropolis’ algorithm forms the spin states of the film. The semi-classical model describes the movement of electrons through the crystal lattice of the film. The electron participates in chaotic thermal motion and drift under the influence of an electric field. The external magnetic field creates magnetization in the antiferromagnetic film. The magnetic moment of the film affects the movement of electrons through the exchange interaction between the spins of atoms and electrons. The simulated system includes a non-magnetic conductive film and an antiferromagnetic film. The spinpolarized electric current is injected through a non-magnetic film. Simulations showed two mechanisms for electrical resistance growth. The first mechanism is associated with electron filtration at the interface between the non-magnetic film and the antiferromagnetic film. The second mechanism is associated with the formation of domains acting as impurities and leading to electron scattering. These two mechanisms give maximum resistance at different magnetic field strengths. The addition of these two mechanisms gives a nonlinear law of magnetoresistance growth as the magnetic field increases.