A sensing circuit reads the magnetic state of individual memory cells making up a nonvolatile magnetic random access memory (MRAM) array. 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...http://www.google.de/patents/US5793697?utm_source=gb-gplus-sharePatent US5793697 - Read circuit for magnetic memory array using magnetic tunnel junction devices 
