The present memory structure includes thereof a first conductor, a second conductor,
a resistive memory cell connected to the second conductor, a first diode connected
to the resistive memory cell and the first conductor, and oriented in the forward
direction from the resistive memory cell to the first conductor, and a second diode
connected to the resistive memory cell and the first conductor, in parallel with
the first diode, and oriented in the reverse direction from the resistive memory
cell to the first conductor. The first and second diodes have different threshold voltages.