Flash memory stores everything from the tunes on your iPod to the photos on your smart phone.

Since first introduced in 1990, the capacity of flash memory has doubled nearly 15 times in the last two decades, allowing users to store ever more songs, pictures and videos on small devices for less money.

But there's a finite limit for flash memory, and the industry may reach it within the next five years, computer scientists say.

So in research labs across the country scientists have been seeking to develop the next generation of memory.

Chemist Jim Tour and his colleagues at Rice University believe they have found a possible solution with plain old silicon dioxide, the most common mineral in the Earth's crust.

It turns out that, under certain conditions, an electric charge applied to tiny bits of silicon dioxide will repeatedly break and reconnect its crystals.

The breaks in the crystal can be used to store information.

Not a new discovery

This kind of phenomenon was noticed in the 1960s, but because it occurs on such a small scale — the nanocrystal wires are about 5 billionths of a meter wide - those researchers couldn't effectively manipulate it, Tour said.

Now, as the science of nanotechnology matures, scientists are beginning to control the interactions of handfuls of electrons, and they're making striking finds as they do so.

"We rediscovered something that people had seen 40 years ago," Tour said.

The discovery, led by Tour, Rice professors Douglas Natelson and Lin Zhong, and one of Tour's graduate students, Jun Yao, is significant because it has the potential to store far more information than a flash drive. It is reported in the journal Nano Letters.

Conventional memory needs three inputs into the device, and this means it can only be arrayed in two dimensions. Tour's silicon dioxide memory needs just two inputs so it can be stacked in three dimensions, increasing its capacity.

Common material

There's another benefit from the fact that the new memory is built out of silicon dioxide, a material commonly used in manufacturing processes.

The hard material is used in everything from making glass to plaque-scrubbing toothpaste.

"It's important that there's nothing really new here the industry has to learn to manufacture this," Tour said.

Of course considerable research and development needs to be done before taking this laboratory discovery into the manufacturing plant.

Tour said he's already collaborating with Austin tech company PrivaTran to develop the memory chips.

With a few years remaining in the growth of flash memory, the computer industry has about half a dozen candidates in various stages of development that may become the standard of memory after flash hits the wall.

Tour said he's hopeful the silicon dioxide memory will be among the candidates.