Ballistic Bit Addressing in a Magnetic Memory Cell Array

In this work a ringing free bit addressing scheme for magnetic random access memories (MRAM) is presented which allows MRAM operation with ultra high write rates above 1 GHz. The results are obtained using single spin simulations of the magnetization dynamics of an MRAM free layer during pulse application. Like in conventional MRAM bit addressing the switching of a selected cell is obtained by the superposition of two half-select field pulses. For ballistic bit addressing the pulses are tailored to obtain optimized trajectories both for the case of switching and non-swichting of the cell: (i) a cell which is selected for magnetization reversal switches ballistically by a half precessional turn of the magnetization; (ii) a cell which is exposed to a magnetic field pulse but which is not selected for switching undergoes a full precessional turn of the magnetization. In both cases the magnetization is near the equilibrium orientation along the easy axis upon pulse decay and ringing of the magnetization is suppressed.