A device for storing information bits using the electrons’ spins instead of their charges (as used in DRAM). The basic unit of MRAM is a GMR (giant magnetoresistance) or TMR (tunnelling magnetoresistance) trilayer structure. Conventional RAM computer chips based on semiconductors store information as long as electricity flows through them. Once the power is turned off, the information is lost. MRAM, however, retains information after a power supply is cut off as the magnetic domain retains its orientation. MRAM has the advantages of both the high speed of static RAM (solid-state memory) and the high density of DRAM, which enable computers to start instantly and to be accessed faster, while consuming less power than conventional semiconductor electronic memory.