Magnetoresistive random access memory

Figure 2.23: A depiction of how data can be accessed in MRAM; light blue areas represent the read path. Between the purple tracks, from top to bottom: free ferromagnet (yellow), tunnel junction (dark blue), pinned ferromagnet (green), antiferromagnet (red), seed layer (dark green)

In 1974 IBM Research developed the magnetic tunnel junction, the main component of magnetostatic random access memory (MRAM). This tunnel junction is a sandwich of ferromagnetic and antiferromagnetic material between columns of bits and rows of words, allowing an ``$[x,y]$''-like access to individual bits within the memory; this can be seen in figure 2.23.

MRAM has the potential to be fast and dense, but even more importantly, it is non-volatile i.e. it does not require a constant application of power to retain its state), unlike standard dynamic random access memory (DRAM). This non-volatility provides another benefit in the form of low-power consumption, making MRAM ideal for applications where power is paramount, such as laptop and palmtop computers, mobile telephones and portable music systems.

To help understand which particle shapes are useful as part of a typical MRAM configuration (Teherani et al., 1999), it is beneficial to study these through simulation.