EMERGING TECHNOLOGY -based superconductors reinforce link to magnetism BRIEFS A new class of iron-oxyarsenide-based superconductors discovered earlier this year shares IDES Inc., a plastic similar unusual magnetic properties with previously known high-temperature superconductors materials information based on -oxide materials, report researchers at the National Institute of Standards and management company, Technology, Gaithersburg, Md. The work emphasizes a critical but as yet unexplained link be- and Firehole Technologies Inc., a tween magnetism and high-temperature superconductors. developer of innovative The importance of magnetism to high-temperature superconductors is remarkable because simulation technologies magnetism strongly interferes with conventional, low-temperature superconductors, but now for composite materials may prove to be an integral element of such materials. and structures, have The team used neutron beams to demonstrate that, like copper-oxide superconductors, the entered into a strategic new iron-oxyarsenide HTc materials discovered by Japanese researchers share an unusual partnership to develop a magnetic structure with magnetically active layers interspersed with layers of nonmagnetic searchable composite material. materials database. For more information: Qingzhen Huang, National Institute of Standards & Technology, 100 www.ides.com Bureau, Gaithersburg, MD 20899; tel: 301/ 975-6164; [email protected]; www.nist.gov. Intel Corp., Samsung Electronics, Copper nanowire arrays grown on different surfaces and Taiwan A simple process to grow upright copper nanowires on a variety of materials is under develop- Semiconductor ment by researchers at the University of Illinois in Urbana Champaign. The nanowire arrays Manufacturing could be suitable for field-emission displays, a new type of display technology that promises to pro- Company (TSMC) vide brighter, more vivid pictures than ex- have reached agreement on the need for industry- isting flat-panel displays. In such an applica- oxide wide collaboration to tion, the nanowires would fire electrons at nano-wire builds target a transition to particles on a screen, lighting them larger, 450-mm size oil-absorbing paper up. These field-emission displays would work wafers starting in 2012. A mat of potassium manganese oxide nanowires with on a similar principle as cathode ray tubes, www.intel.com the touch and feel of paper that can absorb up to 20 but instead of a single electron gun, millions of times its weight in oil, and can be recycled many times, tiny electron emitters shoot electrons at red, Leica Microsystems has reportedly been developed by researchers at the green, and blue coated on a screen. announces that it has acquired Bal-Tec AG, Massachusetts Institute of Technology, Cambridge. “What The new method is based on chemical vapor Liechtenstein, a we found is that we can make ‘paper’ from an interwoven deposition. The substrate, which could be sil- manufacturer of both mesh of nanowires that is able to selectively absorb icon, glass, , or plastic, is exposed to va- mechanical and cryo hydrophobic liquids from ,” pors of a copper-containing compound at 200 sample preparation says Prof. Francesco Stellacci. to 300°Celsius. The resulting copper nano- equipment for scanning The nanowires are stable at high temperatures. As a wires that grow on the substrate are between electron microscopy and result, oil within a loaded membrane can be removed by 70 and 250 nm wide, and are five-sided, with transmission electron microscopy. Products heating above the boiling point of oil. The oil evaporates, a sharp pentagonal tip. The copper nanowires are suitable for such as the EM VCT100 and can be condensed back into a liquid. The Vacuum Cryo Transfer FEDs because they are uniform and have a membrane — and oil — can be used again. system for SEM, and the Two key properties make the system work. First, the very pointed tip. The smaller the tip, the EM HPM100 High nanowires form a spaghetti-like mat with many tiny stronger the electric field, making them very Pressure Freezing unit, pores that make for good capillarity, or the ability to efficient electron emitters even with a very are now available from absorb liquids. Second, a water- repelling coating keeps small voltage. The nanowires emit electrons Leica Microsystems. www.leica-microsystems. water from penetrating into the membrane. Oil, however, at 100 volts, versus many kilovolts needed com isn’t affected, and seeps into the membrane. for the filament of a cathode-ray tube. For more information: Francesco Stellacci, For more information: Yugang Sun, Argonne Massachusetts Institute of Technology, Cambridge, MA National Laboratory, 9700 S. Cass Avenue, Ar- 02139; tel: 617/452-3704; [email protected]; gonne, IL 60439; tel: 630/252-2000; ygsun@ www.mit.edu. anl.gov; www.anl.gov. ADVANCED MATERIALS & PROCESSES/AUGUST 2008 17 BRIEFS Stanford University nanotubes make complete microcircuit chemists have developed a Carbon nanotubes that deposit themselves flat on a surface in a random but relatively even new way to make transistors manner to create a single complete metallic micro-circuit have reportedly been made by Uni- out of carbon nanoribbons. Graphene nanoribbons less versity of Warwick researchers Ioana Dumitrescu, Professor Julie Macpherson, Professor than ten nanometers wide Patrick Unwin, and Neil Wilson. The researchers used a form of chemical vapor deposition can operate at higher tem- and lithography to create the ready made disc shaped single walled carbon nanotube based peratures. A chemical ultramicroelectrodes. process developed by the re- The low surface area of the conducting part of the disc means that they can be used to searchers has made the screen out background “noise” and cope with low signal to noise ratios, making them up to nanoribbons smoother and 1000 times more sensitive than conventional ultramicroelectrodes sensors. This property also narrower than those made produces very fast response times allowing them to respond ten times faster than conven- by other techniques. Hongjie Dai, [email protected]. tional ultramicroelectrodes. The new ultramicroelectrodes also open up interesting possibilities for in fuel cells. SUSS MicroTec, a leading Up till now researchers had been aware that this form of carbon nanotubes appeared to be supplier of process and test particularly useful in the area of catalysis but there was uncertainty as to whether it was the for the semicon- properties of the carbon nanotubes per se that provide this benefit. ductor industry, announces For more information: Patrick Unwin, University of Warwick, England; tel: 4 (0) 2476 523264; that u-ITC, Korea, has se- [email protected]; www.warwick.ac.uk. lected the advanced wafer bonding equipment of SUSS for its MEMS foundry. Porous glass microspheres www.suss.com store , filter Porous wall-hollow glass microspheres that consist of porous glass microballoons that are NASA Ames Research 2 to 100 m in diameter have reportedly been developed at the Savannah River National Lab- Center is developing oratory, Aiken, S.C. The key characteristic of these spheres is an interconnected porosity in durable, oxidation-resistant, foam thermal protection sys- their thin outer walls that can be produced and varied on a scale of 100 to 3000 Ångstroms. tems (TPSs) that would be Researchers G.G. Wicks, L.K. Heung, and R.F. Schumacher have been able to use these suitable for covering large open channels to fill the microballons with absorbents and other materials. Hydrogen or exterior spacecraft surfaces. other reactive gases can then enter the microspheres through the pores, creating a relatively safe, The TPSs would have low to contained, -state storage system. Photographs of these glass-absorbent composites also re- moderate densities, and tem- veal that the wall porosity generates entirely new nanostructures. perature capabilities compa- The porosity can be altered and controlled in various ways that allow the spheres to filter rable to those of carbon- mixed gas streams within a system. Another feature of the microballoons is that their me- based TPSs, which are chanical properties can be altered so they can be made to flow like a liquid. This suggests that reusable at 1650°C (3000°F). These foams might an existing infrastructure that currently transports, stores, and distributes liquids such as the be useful as catalyst supports existing gasoline distribution and retail network can be used. This property and their relative and filters on and in strength also make them suitable for reuse and recycling. outer space. For more information: Angeline French, Savannah River National Laboratory, Aiken, SC http://link.abpi.net/l.php?2 29808; tel: 803/725-2854; [email protected]; www.srnl.doe.gov. 0080612A8

Purdue University has es- Phosphate cement stabilizes tablished a center focused radioactive waste streams on the development of ana- A phosphate cement with added and iron efficiently blocks neutrons and gamma lytical instruments critical to rays emitted by nuclear materials, enabling safer nuclear storage, report materials scientists at a wide range of fields in- Argonne National Laboratory, Argonne, Ill. The material was developed in a collaboration cluding health care and na- tional security. The Center between Argonne, the Russian Federal Nuclear Center, and Ceradyne Boron Products LLC. for Analytical Instru- Ceramicrete was developed several years ago at Argonne, but the collaborators modified the mentation Develop- original Ceramicrete by adding boron to block neutrons, and iron-containing materials to ment will foster collabora- block gamma rays, making it one of the few materials that provides a shield against both tions among the leading forms of radiation. Other materials, such as stainless steel, provide a viable shield from gamma institutions in the field, in- rays but fail to insulate neutrons. cluding Purdue, the Univer- After the scientists determined that the cement successfully absorbed neutron radiation, sity of Illinois, Indiana Uni- Ceradyne built and tested prototype shields, then marketed the material under the name versity, and the University of BoroBond. Working with Department of Energy contractors, Ceradyne has introduced the Notre Dame. www.purdue.edu BoroBond shields for storage of nuclear materials in Oak Ridge, Tenn. These contractors have built several hundred BoroBond-based casks that now house nuclear material. For more information: Jim Waugh, Ceradyne Inc., 3169 Red Hill Avenue, Costa Mesa, CA 92626; tel: 800/839-2189; www.ceradyne.com. 18 ADVANCED MATERIALS & PROCESSES/AUGUST 2008