| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for writing and reading data bits larger than 2-data bits to and from an MRAM cell, in which the MRAM cell is constituted by a magnetic tunnel junction formed of a reading layer exhibiting a reading magnetization direction, and a storage layer including a first storage ferromagnetic layer exhibiting a first storage magnetization direction and a second storage ferromagnetic layer exhibiting a second storage magnetization direction. <P>SOLUTION: This method comprises: a step of heating a magnetic tunnel junction at a temperature higher than a high-temperature threshold; and a step of orienting a first storage magnetization direction to a second magnetization direction at a certain angle. As a result, the magnetic tunnel junction reaches one resistance state level determined by the first storage magnetization direction relative to a reading magnetization direction. In this method, by using only one current line for generating a writing region, at least four different state levels can be stored in an MRAM cell. <P>COPYRIGHT: (C)2013,JPO&INPIT |
