EVENTS, ADVANCES, AND NEWS
■ BY JEFF ECKERT
SPLIT MAGNET SETS RECORD
At 25 tesla (T), it's not the absolute most powerful magnetic device ver built, but apparently it's top dog in the "split magnet"
category, i.e., a magnet that is fabricated in two halves, with holes to
allow the observation of experiments conducted at its core. Earlier
this year, the custom-built, $2.5 million system, located at the
National High Magnetic Field Laboratory at Florida State University
www.magnet.fsu.edu), easily broke the previous record of 17. 5 T, set
by the French in 1991. In addition, it has 1,500 times as much room for
experiments in its "bore," where four large, elliptical ports provide direct horizontal access to the central experimental space.
Building a magnet system with ports strong enough to withstand this physical stress was once considered physically
impossible. After all, the structure has to withstand 500 tons of pressure pulling the two halves together while allowing
160,000 A of electrical current and 3,500 gallons of cooling water per minute to flow through it. However, through
some innovative design work, extensive testing, and locating people who could actually build the thing, it was achieved.
Not much specific information was provided about how the magnet will be employed, but it was revealed that
"researchers in chemistry, physics, and biology are poised to conduct research using the split magnet, while others are
optimistic about the potential for breakthroughs in nanoscience and semiconductor research."
The lab also holds the world's record for magnetic strength at 45 T, achieved by a hybrid (i.e., part resistive and part
superconducting) device. The 11,000 sq ft lab houses a variety of research magnets, but only one or two can be
operated at a time — the power system can handle only a measly 56 MW. Even so, the lab consumes seven percent of
all the electricity used in its hometown of Tallahassee, FL. There's an open house at the lab every February, so check
the website for the exact date if you expect to be in the neighborhood. ▲
■ Interior portion of the split coil magnet.
MEMORY GOING SOFT
For the most part, when your memory starts to go soft, it is not a good thing. Take my word for it. But researchers from North Carolina State
www.ncsu.edu) have developed a memory device "with the
physical properties of Jell-O" that seems to have some useful properties.
Apparently, it functions well in wet environments which is "opening the
door to a new generation of biocompatible electronic devices."
We're talking about a "memristor" type of device which — in the
better-known Hewlett-Packard rendition — is composed of two layers of
titanium dioxide connected by wire. In the NCSU version, the device is
made using a liquid gallium/indium alloy set into a water-based gel.
When you expose the alloy electrode to a positive charge, it creates an
oxidized skin that resists the flow of electricity equivalent to a binary 0.
When you expose it to a negative charge, it becomes conductive, giving
us a 1. As explained in an NCSU press release, "Normally, whenever a
negative charge is applied to one side of the electrode, the positive charge would move to the other side and create
another oxidized skin — meaning the electrode would always be resistive. To solve that problem, the researchers ’doped’
one side of the gel slab with a polymer that prevents the formation of a stable oxidized skin. That way, one electrode is
always conducive — giving the device the 1s and 0s it needs for electronic memory.
At this point, the device is just a prototype that admittedly is not yet capable of holding significant amounts of
memory. However, because the gels used in the technology offer a high level of biocompatibility, it offers the promise of
interfacing electronics directly with biological systems, e.g., living cells or tissues. ▲
■ NCSU's soft memristor-type device
functions in wet environments.