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2012-2 Karl Gschneidner

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Weather permitting, Karl Gschneidner still rides his bike several miles back and forth to work every day as he has for much of his tenure at the Ames Laboratory.

Even after 61 years, showing up at the office most work days is never a chore for Ames Lab senior metallurgist Karl Gschneidner Jr. And the main reason this world-renown researcher, affectionately known as “Mr. Rare Earth,” comes to work is the same one that’s powered him from the start – he’s having fun!

“If it wasn’t still fun, I’d have retired years ago,” Gschneidner says. “I enjoy what I do and have always tried to do my best. There’s still plenty to learn so I keep at it!”

His crowded office in Spedding Hall is a testament to Gschneidner’s reputation and staying power.  Dozens of awards, including a National Academy of Engineering membership, cover a fair amount of the available wall space, and floor-to-ceiling bookcases hold a career’s worth of reference materials. Multiple file cabinets hold volumes of notes, presentations and articles and neat stacks of unfiled work cover the tops of a desk and two tables.

Much of it bears Gschneidner’s name –he published his 500th refereed research journal article earlier this summer, in addition to untold numbers of presentations, lectures and keynote addresses.

An early love of chemistry and physics set Gschneidner on his career path, but it wasn’t until he attended graduate school at Iowa State University, and worked as a research associate at Ames Laboratory, that he became involved in the study of rare earths.

“I’d been interested in the metallic elements alloys, but it wasn’t until I came here that I began working with rare-earth materials,” he says, “and Ames Laboratory has always been THE place when it comes to the rare earths. It was such a fascinating field, I never really considered anything else.”

Advances in technology, particular computational power and refinements in analytic instrumentation, have been invaluable to Gschneidner’s work.

“One of my first assignments as a new graduate student was to produce a 500-gram sample of gadolinium for another senior grad student to study,” he explains. “It took him months of work to plot the heat capacity as a function of temperature.  The chart was a roll of paper that extended clear down the hall.

“Now, we can take a very small sample, put it in the calorimeter and the process is entirely automated,” he continues. “We can get the same results overnight that required months before. You can’t beat that.”

ImageGadolinium has been one of several focal points of his research, particularly its ability to exhibit a giant magnetocaloric effect, or GMCE  – it heats up when exposed to a magnetic field and cools down when the field is withdrawn.

Gschneidner was instrumental in development of refrigerators that harnessed this phenomenon in place of traditional gas-compression-driven cooling.

“The biggest stumbling block we now face is coming up with a GMCE material that doesn’t progressively break down into smaller pieces over the billions of magnetization/demagnetization cycles required for a 15-20-year appliance life,” he says. “We also need to reduce the time dependence of the transformation.”

Based on the current pace of research and the growing number of working prototypes around the world, Gschneidner expects magnetic refrigeration to become commercially viable by 2016 or so, a fruition he plans to witness.

“We’re finding all kinds of new phenomena in low temperature and low magnetic field research,” he says, “and that’s what brings me back to the laboratory.”

~ by Kerry Gibson