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: Long-standing recycling of ancient sulfur in billion-year-old rocks supplies energy to terrestrial subsurface biosphere

Related Stories

Iron-loving bacteria a model for Mars life

October 26, 2016

Single-celled microbes are considered a living example of the kind of life that might exist elsewhere in the Universe, as they are able to survive some of the extreme conditions that exist on other worlds.

Apple patent reveals idea for fingerprint technology

October 6, 2016

(Tech Xplore)—"Capacitive fingerprint sensor including an electrostatic lens" is the title of the patent filed in September 2014.The inventor listed is Jean-Marie Bussat. This is being talked about in this week's tech press ...

Achieving ultra-low friction without oil additives

October 11, 2016

Researchers at Georgia Institute of Technology have developed a new process for treating metal surfaces that has the potential to improve efficiency in piston engines and a range of other equipment.

Recommended for you

Self-sealing syringe prevents blood loss in hemophilic mice

October 28, 2016

(—For people whose blood does not clot appropriately, such as those with hemophilia, diabetes, or cancer, getting an injection or blood draw with a hypodermic needle is not a trivial matter. Because the needle ...

Closer look reveals tubule structure of endoplasmic reticulum

October 28, 2016

(—A team of researchers from the U.S. and the U.K. has used high-resolution imaging techniques to get a closer look at the endoplasmic reticulum (ET), a cellular organelle, and in so doing, has found that its structure ...

Gaia spies two temporarily magnified stars

October 28, 2016

While scanning the sky to measure the position of over one billion stars in our Galaxy, ESA's Gaia satellite has detected two rare instances of stars whose light was temporarily boosted by other celestial objects passing ...

Changing semiconductor properties at room temperature

October 28, 2016

It's a small change that makes a big difference. Researchers have developed a method that uses a one-degree change in temperature to alter the color of light that a semiconductor emits. The method, which uses a thin-film ...


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.