| 摘要 |
The present disclosure concerns a method for writing and reading a plurality of data bits to a magnetic random access memory (MRAM) cell (1) comprising a magnetic tunnel junction (2) formed from a read magnetic layer (21) having a read magnetization (210), a tunnel barrier layer (22), and a storage layer (23); the storage layer (23) comprising a first storage ferromagnetic layer (230) having a first storage magnetization (233), a second storage ferromagnetic layer (231) having a second storage magnetization (234) that can be freely oriented at a high temperature threshold, and a storage anti-parallel coupling layer (232) magnetically coupling the first and second storage magnetization (233, 234), an antiferromagnetic layer (24) which pins at the functioning temperature the storage layer (23) and a field line (41); comprising: heating the magnetic tunnel junction (2) over a high temperature threshold; orienting the first and second storage magnetization (233, 234) until the first storage magnetization (233) forms a predetermined angle (±) with respect to the second storage magnetization (234) such as to reach a predetermined resistance state level of the magnetic tunnel junction (2) determined by the orientation of the first storage magnetization (233) relative to the read magnetization (210); and cooling the magnetic tunnel junction (2) to a low temperature threshold to freeze the second storage magnetization (234) at the predetermined angle (±). The method allows for storing at least four distinct state levels in the MRAM cell using only one current line to generate a writing field. |
