Micromagnetic simulation of write operation in Gbit-MRAM memory cell

摘要

Write-operation in magnetic random access memory (MRAM) with bit density of Gbit/cm{sup}2 order has been numerically simulated for low sub-micron scale magnetic cells. The calculated results show that the amplitude of I{sub}w is proportional to t/w, while that of ΔE is proportional to wt{sup}2. To obtain the sufficient energy barrier against a thermal fluctuation (ΔE80k{sub}BT, at 300 K), the thicker magnetic cell is required as the cell is downsized for high-density memory applications, although the thinner one is preferred form the view point of minimizing the switching current. The margin of the switching current for selective write-operation is decreased with decreasing the lateral aspect ratio of the cell. The addressability for the write-operation is also degraded by the formation of structural defect in the cell. In this paper, practical tolerance of the structural defect in the magnetic cell applicable for Gbit-MRAM are discussed.