Multiscale micromagnetic simulation of giant magnetoresistance read heads

Abstract

The Landau-Lifshitz-Gilbert equation and quasistatic Maxwell equations were solved simultaneously to calculate the read back signal of giant magnetoresistance read heads with a hybrid finite-element/boundary element method. The finite-element simulations show the influence of the sense current on the linearity of the reader, the effect of the exchange bias field on the sensor performance, and the influence of the Gilbert damping constant on the decay time of the read back voltage. All parts of the system, the layers of the giant magnetoresistance sensor, the hard bias magnets, the shields, and the recording layer are treated micromagnetically. In addition, the influence of the sense current onto the magnetization is taken into account self-consistently. The current distribution in the giant magnetoresistance stack is calculated from local resistivity which depends on the magnetization of the free and of the pinned layer.