Embedded control: Solid-state research aims at advanced devices

Oak Ridge, TN — Complex materials such as transition metal oxides and the cuprates rely on a fine balance of energies within their structures to create desirable macroscopic properties, such as colossal magnetoresistance (CMR) and high-temperature superconductivity. According to an article published online by Alexander E. Braun, Senior Editor at Control Engineering sister publication Semiconductor International, researchers at Oak Ridge National Laboratory (ORNL) are studying these effects to help improve existing semiconductor systems, such as spin valves, magnetoresistive random access memories (MRAM) or photovoltaics useful for embedded control systems.

Spatial confinement affects transport of charge carriers passing through a region of high resistance. (Source: Oak Ridge National Laboratory)

The crux of the matter is the CMR effect, which originates in phase separation of crystal domains at the

nanometer scale

. The Oak Ridge researchers have shown that by spatially confining a phase-separated material, it is possible to harness not only the properties of the metallic regions in a structure, but also those of the coexisting insulating regions. The overall electronic characteristics of these devices can be vastly different from a bulk or thin-film device of the same material. Observing the CMR effect may make it possible to figure out exactly how these phase transitions and interactions actually feed and create the observed properties.Computer hard drives and similar devices use the much smaller giant magnetoresistance (GMR) effect. Having available material that is orders of magnitude more strongly affected by a magnetic field could have significant large-scale storage and device implications. The research is funded by the Department of Energy and the National Science Foundation. — C.G. Masi , senior editor Control Engineering News Desk Register here and scroll down to select your choice of eNewsletters free.

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