1. A memory unit comprising: a giant magnetoresistance cell electrically coupled between a write bit line and a write source line, a write current passing through the giant magnetoresistance cell switches the giant magnetoresistance cell between a high resistance state and a low resistance state, the giant magnetoresistance cell comprises a free magnetic layer separated from a first pinned magnetic layer by a first non-magnetic electrically conducting layer; and a magnetic tunnel junction data cell electrically coupled between a read bit line and a read source line, the magnetic tunnel junction data cell is configured to switch between a high resistance state and a low resistance state by magnetostatic coupling with the giant magnetoresistance cell, and be read by a read current passing though the magnetic tunnel junction data cell, the magnetic tunnel junction data cell comprises the free magnetic layer separated from a second pinned magnetic layer by an oxide barrier layer.