A memory device having a memory portion connected in series with a
threshold device between. The memory portion stores at least one bit of
data based on at least two resistance states. The threshold device is
configured to switch from a high resistance state to a low resistance
state upon application of a voltage and, when the voltage is removed, to
re-assume the high resistance state. Additionally, the threshold device
can be configured to switch in response to both negative and positive
applied voltages across the first and second electrodes. Memory elements
having a memory portion and threshold device between first and second
electrodes and methods for forming the memory elements are also provided.