College of Engineering News • Iowa State University

Nlebedim wins best poster presentation award

Ikenna Nlebedim
Ikenna Nlebedim

by Thane Himes

Ikenna Nlebedim, ECpE and Ames Laboratory postdoctoral research associate, won an award for best poster presentation at the 12th Joint MMM/INTERMAG Conference in January. In 2011, he received the best postdoctoral research associate presentation award.

Nlebedim’s presentations are based on his work with functional materials, specifically magnetostrictive materials, which are materials that change shape or dimension when exposed to a magnetic field. These energy conversion materials have applications in sensors and actuators, among other things.

“We are working to drive magnetic research from laboratories to markets,” Nlebedim said.  “Our work has a lot of industrial relevance.”

The higher the level of magnetostriction in a material, the more the material strains with exposure to magnetic field. For the sake of efficiency, it is desirable to produce the most strain with smallest amount of magnetic field, which defines the sensitivity of a magnetostrictive material. To increase sensitivity, Nlebedim substitutes positively-charged ions, or cations, into cobalt ferrite. This practice, however, reduces overall magnetostriction. Nlebedim is working to create materials with the right balance of both properties.

In an article published in IEEE Transactions on Magnetics, Nlebedim and colleagues presented a material derived from cobalt ferrite in which both properties were improved.  His goal is to create a material that could, in some instances, replace Terfenol-D, a highly-magnetostrictive material made from rare-earth elements and originally made practical at Ames Laboratory in the 1980s. Developing high-sensitivity magnetostrictive materials with cobalt ferrite, a more commercially available material, makes more economic sense than using Terfenol-D, in some applications.

“The ability to fabricate high quality materials and systematic characterization are vital in our research,” Nlebedim said. “Ames Lab is the perfect place for us.”

When Nlebedim presented his poster at the conference in January, a woman walked up to him and asked him a number of questions.  Nlebedim answered with assured details.

“She said I sounded very confident,” Nlebedim said. “And of course I was. I’ve been working on this for years.”

It turns out that woman was one of the session chairs selecting posters for the best presentation award. Nlebedim didn’t know he was being considered for a best presentation award, so finding out that he won was a shock.

“I was surprised and a little embarrassed, “Nlebedim said. “I wasn’t really competing; I just wanted to present my work.”

This isn’t the first time Nlebedim’s been honored at an international conference. He was part of an ECpE team, led by PhD student Orfeas Kypris, that won a best presentation award for presenting “Stress depth profiling for non-destructive testing using magnetic Barkhausen noise signals” at the 2011 MMM Conference in Scottsdale, Ariz.

Nlebedim’s work with magnetostrictive materials isn’t done yet. Currently, he is working on producing thin films of his magnetostrictive cobalt ferrite and its derivative materials. He also is developing magnetic sensors for non-destructive evaluation and is part of the transcranial magnetic stimulation team, which is using magnetic fields to activate neurons to help study brain functions in a non-invasive way.