These devices are classified as generic memristors based on their response to a sinusoidal input signal over a frequency range of 0.5 Hz to 100 kHz. The devices can be programmed over a continuous range of resistance states using two techniques: DC compliance current limiting and pulsed operation. Consecutive pulsing can selectively place a device into a desired resistance range, either through consecutive erase or write pulses. This range can be selected by varying the number of pulses applied, the pulse width, and/or the pulse amplitude. The data retention in each intermediate resistance state is currently under study and depends upon the conditions used to program the device.

ACKNOWLEDGMENTS
This work was partially supported by a grant from the National Science Foundation, grant no. CCF-1320987, the United States Air Force Office of Scientific Research, DEPSCoR Grant No. FA9550-07-1-0546, and by the United