A recent report from Hewlett-Packard (HP) outlines a small breakthrough in a technology that could find its way into the next generation of computer memory, replacing both flash and DRAM. Called a memristor, the device was first postulated in 1971 by Professor Leon Chua of the University of California, Berkeley. While physicists today recognize three basic circuit properties known as resistance, capacitance, and inductance, Professor Chua argued there was a fourth property: one that results in a permanent change to the resistance of a material. Devices exhibiting this property he dubbed memristors.
The current memristor design consists of two layers of titanium dioxide (TiO2) with one layer being oxygen deficient sandwiched between two electrodes. The oxygen-deficient layer contains positive charges, making it a good conductor. The standard TiO2 layer has a higher resistance. A positive voltage applied to the oxygen-deficient layer forces the positive charges into the standard layer, making it similar to the oxygen deficient layer's conductivity. The overall resistance of the material drops. Reversing the polarity draws the positive charges out of the standard layer, boosting resistance. The amount of resistance determines if that particular path represents a binary 1 or 0. Interestingly, the charges do not migrate when power is removed, letting the memristor remember it's resistance value when power is reapplied.
HP plans to release a memristor-powered device to rival solid-state drives (SSDs) in a year-and-a-half. with replacements for DRAM's and eventually SRAM's coming by 2015.
How does it work — a memristor video primer: