A magnetoresistive device is provided with separate read and write
architecture. In one embodiment, a magnetic tunnel junction (MTJ) has a
nonmagnetic nonconductive barrier layer sandwiched between two
ferromagnetic conducting layers. A first read line having a first
resistance is coupled to a first ferromagnetic layer and a second read
line having a third resistance is coupled to a second ferromagnetic layer
such that a voltage difference between the two read lines will produce a
current flowing perpendicularly through each layer of the MTJ. A first
write line having a second resistance is separated from the first read
line by a first insulator and a second write line having a fourth
resistance is separated from the second read line by a second insulator,
and wherein the second and fourth resistances are lower than the first
and third resistance.