Featured Research

from universities, journals, and other organizations

Perfect faults: A self-correcting crystal may unleash the next generation of advanced communications

Date:
November 6, 2013
Source:
National Institute of Standards and Technology (NIST)
Summary:
Researchers are engineering and measuring a potentially important new class of nanostructured materials for microwave and advanced communication devices. These new multilayered crystalline sandwiches might enable a whole new class of compact, high-performance, high-efficiency components for devices such as cellular phones.

Not a brick wall. Electron microscope image of a cross section of the newly characterized tunable microwave dielectric clearly shows the thick layers of strontium titanate "bricks" separated by thin "mortar lines" of strontium oxide that help promote the largely defect-free growth of the bricks.
Credit: TEM image courtesy David Mueller. Color added for clarity by Nathan Orloff.

Researchers from the National Institute of Standards and Technology (NIST) have joined with an international team to engineer and measure a potentially important new class of nanostructured materials for microwave and advanced communication devices. Based on NIST's measurements, the new materials -- a family of multilayered crystalline sandwiches -- might enable a whole new class of compact, high-performance, high-efficiency components for devices such as cellular phones.

Related Articles


"These materials are an excellent example of what the Materials Genome Initiative refers to as 'materials-by-design'," says NIST physicist James Booth, one of the lead researchers. "Materials science is getting better and better at engineering complex structures at an atomic scale to create materials with previously unheard-of properties."

The new multilayer crystals are so-called "tunable dielectrics," the heart of electronic devices that, for example, enable cell phones to tune to a precise frequency, picking a unique signal out of the welter of possible ones.

Tunable dielectrics that work well in the microwave range and beyond -- modern communications applications typically use frequencies around a few gigahertz -- have been hard to make, according to NIST materials scientist Nathan Orloff. "People have created tunable microwave dielectrics for decades, but they've always used up way too much power." These new materials work well up to 100 GHz, opening the door for the next generation of devices for advanced communications.

Modern cellphone dielectrics use materials that suffer from misplaced or missing atoms called "defects" within their crystal structure, which interfere with the dielectric properties and lead to power loss. One major feature of the new materials, says Orloff, is that they self-correct, reducing the effect of defects in the part of the crystal where it counts. "We refer to this material as having 'perfect faults'," he says. "When it's being grown, one portion accommodates defects without affecting the good parts of the crystal. It's able to correct itself and create perfect dielectric bricks that result in the rare combination of high tuning and low loss."

The new material has layers of strontium oxide, believed to be responsible for the self-correcting feature, separating a variable number of layers of strontium titanate. Strontium titanate on its own is normally a pretty stable dielectric -- not really tunable at all -- but another bit of nanostructure wizardry solves that. The sandwich layers are grown as a thin crystalline film on top of a substrate material with a mismatched crystal spacing that produces strain within the strontium titanate structure that makes it a less stable dielectric -- but one that can be tuned. "It's like putting a queen-sized sheet on a king-sized bed," says Orloff. "The combination of strain with defect control leads to the unique electronic properties."

One key discovery by the research team was that, in addition to adding strain to the crystal sandwich, adding additional layers of strontium titanate in between the strontium oxide layers increased the room-temperature "tunability" performance of the structure, providing a new mechanism to control the material response. The material they reported on recently in the journal Nature has six layers of strontium titanate between each strontium oxide layer.

The new sandwich material performs so well as a tunable dielectric, over such a broad range of frequencies, that the NIST team led by Booth had to develop a new measurement technique -- an array of test structures fabricated on top of the test film -- just to measure its electronic characteristics. "We were able to characterize the performance of these materials as a function of frequency running from 10 hertz all the way up to 125 gigahertz. That's the equivalent of measuring wavelengths from kilometers down to microns all with the same experimental set-up," says Orloff, adding, "This material has a much lower loss and a much higher tunability for a given applied field then any material that we have seen."

An international team of researchers contributed to the recent paper, representing, in addition to NIST, Cornell University, the University of Maryland, Pennsylvania State University, the Institute of Physics ASCR (Czech Republic), Universitat Politθcnica de Catalunya (Spain), the Kavli Institute at Cornell for Nanoscale Science, Oak Ridge National Laboratory, the Leibniz Institute for Crystal Growth (Germany), The University of Texas at Austin and Temple University.


Story Source:

The above story is based on materials provided by National Institute of Standards and Technology (NIST). Note: Materials may be edited for content and length.


Journal Reference:

  1. Che-Hui Lee, Nathan D. Orloff, Turan Birol, Ye Zhu, Veronica Goian, Eduard Rocas, Ryan Haislmaier, Eftihia Vlahos, Julia A. Mundy, Lena F. Kourkoutis, Yuefeng Nie, Michael D. Biegalski, Jingshu Zhang, Margitta Bernhagen, Nicole A. Benedek, Yongsam Kim, Joel D. Brock, Reinhard Uecker, X. X. Xi, Venkatraman Gopalan, Dmitry Nuzhnyy, Stanislav Kamba, David A. Muller, Ichiro Takeuchi, James C. Booth, Craig J. Fennie, Darrell G. Schlom. Exploiting dimensionality and defect mitigation to create tunable microwave dielectrics. Nature, 2013; 502 (7472): 532 DOI: 10.1038/nature12582

Cite This Page:

National Institute of Standards and Technology (NIST). "Perfect faults: A self-correcting crystal may unleash the next generation of advanced communications." ScienceDaily. ScienceDaily, 6 November 2013. <www.sciencedaily.com/releases/2013/11/131106114045.htm>.
National Institute of Standards and Technology (NIST). (2013, November 6). Perfect faults: A self-correcting crystal may unleash the next generation of advanced communications. ScienceDaily. Retrieved November 26, 2014 from www.sciencedaily.com/releases/2013/11/131106114045.htm
National Institute of Standards and Technology (NIST). "Perfect faults: A self-correcting crystal may unleash the next generation of advanced communications." ScienceDaily. www.sciencedaily.com/releases/2013/11/131106114045.htm (accessed November 26, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Wednesday, November 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Who Will Failed Nuclear Talks Hurt Most?

Who Will Failed Nuclear Talks Hurt Most?

Reuters - Business Video Online (Nov. 25, 2014) — With no immediate prospect of sanctions relief for Iran, and no solid progress in negotiations with the West over the country's nuclear programme, Ciara Lee asks why talks have still not produced results and what a resolution would mean for both parties. Video provided by Reuters
Powered by NewsLook.com
Flying Enthusiast Converts Real-Life Aircraft Cockpit Into Simulator

Flying Enthusiast Converts Real-Life Aircraft Cockpit Into Simulator

Reuters - Innovations Video Online (Nov. 25, 2014) — A virtual flying enthusiast converts parts of a written-off Airbus aircraft into a working flight simulator in his northern Slovenian home. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com
Car Park Solution for Flexible Green Energy

Car Park Solution for Flexible Green Energy

Reuters - Innovations Video Online (Nov. 24, 2014) — A British solar power start-up says that by covering millions of existing car park spaces around the UK with flexible solar panels, the country's power problems could be solved. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Microsoft Adds Robot Guards, Ushers In Sci-Fi Apocalypse

Microsoft Adds Robot Guards, Ushers In Sci-Fi Apocalypse

Newsy (Nov. 23, 2014) — Microsoft has robotic security guards working at its Silicon Valley Campus. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins