SAN JOSE, Calif. – For nearly 40 years, scientists have speculated that basic electrical circuits have a natural ability to remember things even when the power is switched off.Researchers at Hewlett-Packard Co. might have proved them right, with a discovery that they hope will lead to memory chips that store more data but consume far less power than those currently used in personal computers and other digital devices.The circuit element – called a memristor – could enable cell phones that can go weeks or longer without a charge, PCs that start up instantly, and laptops that retain your session information long after the battery dies.It also could challenge flash memory, which is widely used in portable electronics because of its ability to retain information even when power is off. Chips incorporating the HP discovery would be faster, suck up less power and take up far less space than flash memory.”It certainly looks promising,” said Wolfgang Porod, professor of electrical engineering at the University of Notre Dame and director of the university’s Center for Nano Science and Technology. “However, if it’s going to be 100 times better or 1,000 times better (than today’s flash), it’s very hard to say at this point.”Scientists have suspected since the 1970s that along with the resistor, capacitor and inductor, a fourth fundamental building block is possible.The memristor built by HP Labs and reported Thursday in the scientific journal Nature is made with a layer of titanium dioxide sandwiched between two metal electrodes. The researchers discovered that the amount of resistance it exerts depends on how much electric charge had passed through it.That characteristic gives the memristor an innate ability to remember the amount of charge that has flowed through it long after its power supply is cut off. That means the circuit itself can be built with a memory function baked in.Otherwise, data have to be stored in power-hungry transistors configured for storage. That also takes up valuable real estate on microprocessors or requires separate memory chips.Some outside researchers, however, said more study is required before the memristor upsets the memory business.”These structures are going to be very small. It’s obvious to me one could make very dense memory out of them, but how it could compete against other memory like flash remains to be seen,” said Porod.

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