Spin dynamics of unit cells in magnetic random access memory

We present a micromagnetic study of the field-induced magnetic switching behavior of memory cells. The analytical expressions of writing fields generated by the current in a conducting line are derived. The effective magnetic field acted on the memory cell from the narrow current-carrying line is larger than the wide one, which results in a smaller switching current threshold. Owing to the flat end shape, the oval cell requires a smaller switching current threshold than the elliptical one. Depending on the initial end domain configuration and the width of a conducting line, the reversal process of field-induced magnetic switching for the full-select cell can be classified into three types, i.e., O, U, and S modes. The mechanism governing the dynamic switching mode is explained.