Patent ID: 7218550

Claim:
A magnetic tunnel junction device ( 30 ) comprising first and second stacks of layers of magnetic material ( 32 , 36 ), each stack comprising at least one layer, the stacks ( 32 , 36 ) being separated by a third stack of layers of non-magnetic material, the third stack ( 34 ) comprising at least one layer of electrically insulating material ( 34 ), with contacts ( 31 , 36 ) being made to the first and second stack ( 32 , 36 ) to apply a voltage across the device, the magnetic materials and insulating material each being of a type and the said layers each having a thickness such that the orientation of the magnetic moments of said first and second stack ( 32 , 36 ) relative to one another are changeable by applying a voltage across the device, wherein said orientation can be switched to a first state by applying a first voltage across the device and said orientation can be switched to a second state applying a second voltage across the device, whereby after either switching the said orientation is maintained when a third voltage is applied to the device, the said third voltage being in between the first and second voltages.