Researchers Discover Surface Orbital 'Roughness' in Manganites

November 20, 2007

Researchers at the U.S. Department of Energy's Brookhaven National Laboratory have shown that in a class of materials called manganites, the electronic behavior at the surface is considerably different from that found in the bulk. Their findings, which were published online in the November 18, 2007, issue of Nature Materials, could have implications for the next generation of electronic devices, which will involve increasingly smaller components.

As devices shrink, the proportion of surface area grows in comparison to the material's volume. Therefore, it's important to understand the characteristics of a material's surface in order to predict how those materials behave and how electrons will travel across an interface, said Brookhaven physicist John Hill.

Hill and his fellow researchers were particularly interested in how the outer electrons of atoms in a so-called manganite material are arranged. Manganites - consisting of a rare-earth element such as lanthanum combined with manganese and oxygen - show a huge change in electrical resistance when a magnetic field is applied. Taking advantage of this "colossal magnetoresistance effect" could be the key to developing advanced magnetic memory devices, magnetic field sensors, or transistors.

The research team, which also includes scientists from KEK (Japan), CNRS (France), Ames Laboratory, and Argonne National Laboratory, used x-ray scattering at Brookhaven's National Synchrotron Light Source and Argonne's Advanced Photon Source to study the orbital order - the arrangement of electrons in the outermost shell - of the material at the surface and in its bulk.

"When you cool down the bulk material to a particular temperature, all the orbitals arrange themselves in a very particular pattern," Hill said. "The question is, does the same thing happen at the surface? And if not, how is it different?"

The authors found that at the surface, the orbital order is more disordered than in the bulk material. And, even though the manganite's crystal surface is atomically smooth, the orbital surface is rough. These characteristics could affect the way electrons are transferred across a material's surface and provide fundamental information for future research and development. Next, the researchers plan to look for this surface orbital "roughness" in other materials and test its effect on magnetism.

Source: Brookhaven National Laboratory, by Kendra Snyder

Explore further: A piece of Mars is going home

Related Stories

Diamonds show promise for spintronic devices

January 29, 2018

Conventional electronics rely on controlling electric charge. Recently, researchers have been exploring the potential for a new technology, called spintronics, that relies on detecting and controlling a particle's spin. This ...

How comet dust reveals the history of the solar system

January 23, 2018

We are not used to considering dust as a valuable material – unless it comes from space. And more precisely, from the comet 67P/Churyumov-Gerasimenko. An analysis of its dust has provided valuable information about this ...

40-year controversy in solid-state physics resolved

February 7, 2018

An international team at BESSY II headed by Prof. Oliver Rader has shown that the puzzling properties of samarium hexaboride do not stem from the material being a topological insulator, as was previously proposed. Theoretical ...

Recommended for you

Pattern formation—the paradoxical role of turbulence

February 19, 2018

The formation of self-organizing molecular patterns in cells is a critical component of many biological processes. Researchers from Ludwig-Maximilians-Universitaet (LMU) in Munich have proposed a new theory to explain how ...

Converting heat into electricity with pencil and paper

February 19, 2018

Thermoelectric materials can use thermal differences to generate electricity. Now there is an inexpensive and environmentally friendly way of producing them with the simplest tools: a pencil, photocopy paper, and conductive ...

Bringing a hidden superconducting state to light

February 16, 2018

A team of scientists has detected a hidden state of electronic order in a layered material containing lanthanum, barium, copper, and oxygen (LBCO). When cooled to a certain temperature and with certain concentrations of barium, ...

0 comments

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.