Simple method may improve computer memory, catalysts, ceramic/metal seals, and nanodevices

August 6, 2004

A method that creates smooth and strong interfaces between metals and metal oxides without high-temperature brazing has been patented by researchers at the National Nuclear Security Administration’s Sandia National Laboratories, Pacific Northwest National Laboratory, and the University of North Texas.

The method can improve magnetic random-access memories, which allow next-generation computers to boot up instantly yet retain their entire memories after power interruptions. Depositing flat, nanometer-thin crystalline and ferromagnetic metallic layers on similarly thin oxide layers increases strength, stability, and uniformity of the oxide-metal interface. This reduces manufacturing cost and requires less electricity to produce more rapid magnetic effects for the computer memory.

The inexpensive technique also may produce better, less expensive (more highly dispersed but stable) catalysts for chemical reactions, better ceramic/metal seals, and lead to improved nanodevices.

The method works by controlling the growth and interfacial strength of a metal deposited on an oxide layer. There are two distinct methods within the patent.

By fully hydroxylating the oxide surface and then cleansing it of impurities, a chemical reaction can oxidize a fraction of deposited metal atoms, incorporating them by strong ionic bonds into the oxide surface. However, these metal atoms also bind strongly to metallic atoms above them and serve as “anchors” to bind more metal. At sufficient concentration, laminar growth is achieved and crystallinity is observed by approximately six metal atomic layers. These findings are supported by both experimental and theoretical results.

Another method controls the wetting characteristics (that is, the layer-by-layer deposition) and increases adhesion between a metal and an oxide layer. By introducing or producing a sub-monolayer of negatively charged species (e.g., a fraction of hydroxyl-radical coverage) to the surface of an oxide layer, layer-by-layer growth of metal deposited onto the oxide surface is promoted. This increases the adhesion strength of the metal-oxide interface. The negatively charged species can either be deposited directly onto the oxide surface or in the form of a compound that dissociates on, or reacts with, the surface to form the negatively charged species. The deposited metal adatoms are thereby bound laterally to the negatively charged species as well as vertically to the oxide surface, binding them strongly to the surface of the oxide, while otherwise they are bound weakly. This method has also been demonstrated by experiment and supported by theory.

Source: DOE/Sandia National Laboratories

Explore further: New processes in modern ReRAM memory cells decoded

Related Stories

New processes in modern ReRAM memory cells decoded

September 29, 2015

Resistive memory cells or ReRAMs for short are deemed to be the new super information-storage solution of the future. At present, two basic concepts are being pursued, which, up to now, were associated with different types ...

Researchers create fatigue-free, stretchable conductor

September 21, 2015

Researchers have discovered a new stretchable, transparent conductor that can be folded or stretched and released, resulting in a large curvature or a significant strain, at least 10,000 times without showing signs of fatigue.

Recommended for you

On soft ground? Tread lightly to stay fast

October 8, 2015

These findings, reported today, Friday 9th October, in the journal Bioinspiration & Biomechanics, offer a new insight into how animals respond to different terrain, and how robots can learn from them.

Ancient genome from Africa sequenced for the first time

October 8, 2015

The first ancient human genome from Africa to be sequenced has revealed that a wave of migration back into Africa from Western Eurasia around 3,000 years ago was up to twice as significant as previously thought, and affected ...

Blue skies, frozen water detected on Pluto

October 8, 2015

Pluto has blue skies and patches of frozen water, according to the latest data out Thursday from NASA's unmanned New Horizons probe, which made a historic flyby of the dwarf planet in July.

New method facilitates research on fuel cell catalysts

October 8, 2015

While the cleaning of car exhausts is among the best known applications of catalytic processes, it is only the tip of the iceberg. Practically the entire chemical industry relies on catalytic reactions. Therefore, catalyst ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.