Modeling the effects of domains in magnetic tunnel junctions

A model based on the domain structure of the electrodes in ferromagnet-insulator-ferromagnet tunnel junctions is derived. It provides an explicit expression of the junction magnetoresistance (MR) in terms of the magnetization of the ferromagnetic layers. The response in magnetic field of junctions with very high and very low MR are simulated, and the lack of fringing field coupling is proposed to be a reason for low MR. The effect of temperature on junction MR is discussed briefly in the context of the model.