US Patent 7741638 - Memristive control layer

http://www.freepatentsonline.com/7741638.html

This appears to be one of HP's patents related to their "memristor" version of RRAM in which a control layer such as TiO2-x is included as a source or sink of oxygen vacancies to control the resistance level. Claim 1 reads:

1. A control layer for use in a junction of a nanoscale electronic switching device, the control layer comprising a material that

1) is chemically compatible with a connecting layer and at least one electrode in the nanoscale switching device and

2) is a source of a material for the connecting layer or a sink for a material from the connecting layer,

the control layer configured to control at least one of electrochemical reaction paths, electrophysical reaction paths, and combinations thereof during operation of the device.

However, at least one prior art patent may have been overlooked during the examination (see US Patent 7148533, column 4, lines 9-34 which teaches using nanoscale thin film oxygen-rich and oxygen deficient layers for resistance switch memory.)