A nonvolatile magnetic random access memory (MRAM) is an array of individual magnetic memory cells. Each memory cell is a magnetic tunnel junction (MTJ) element and a diode electrically connected in series. Each MTJ is formed of a pinned ferromagnetic layer whose magnetization direction is prevented...http://www.google.com.au/patents/US5640343?utm_source=gb-gplus-sharePatent US5640343 - Magnetic memory array using magnetic tunnel junction devices in the memory cells
