APS Honors Two Undergrads with Apker Award

Peter Onyisi Nathaniel Stern

Two young physicists have been honored with the 2004 Apker Award for their outstanding undergraduate research. The APS presents two Apker awards annually, one to a student from a PhD-granting institution, one to a student from an non-PhD-granting institution. The recipients, who will each receive $5,000, were selected by a committee from a group of six finalists.

Peter Onyisi of the University of Chicago received the award for a PhD-granting institution for his research entitled, "Looking for New Invisible Particles." Nathaniel Stern of Harvey Mudd College received the award for a non-PhD-granting institution for his thesis entitled, "Exchange Anisotropy and Giant Magnetoresistance in Thin Film Spin Valves Containing Ultra-thin IrMn Antiferromagnetic Layers." Onyisi's research involved searching for evidence of new particles in data from proton-anti-proton collisions at 1.8 TeV, using data collected by the Collider Detector at Fermilab (CDF).

After analyzing photon and missing energy events for evidence of supersymmetric particles or particles lost to extra dimensions, Onyisi observed no deviation from the Standard Model, and as a result placed new limits on contributions from new physics.

Onyisi published these results in Physical Review Letters in 2002. He also authored a number of internal CDF notes on his research and presented his work at the April APS meetings in 2001 and 2003.

Onyisi received his BA in physics and applied mathematics in June 2003, and is now a graduate student in physics at Cornell University with an NSF Graduate Research Fellowship.

Stern investigated the magnetic exchange interaction between nanoscale antiferromagnetic films and ferromagnetic films.

Though these structures are the basis for magnetic sensor and magnetic storage devices, the exchange interaction is not fully understood.

Stern demonstrated that magnetic exchange biasing occurs with antiferromagnetic film thicknesses that are substantially less than was previously thought possible, showing that existing theories are inadequate to explain the interaction.

Stern published his research in the Journal of Applied Physics, and presented at several conferences. He received his BS in May 2003, and is now pursuing graduate studies in physics at the University of California, Santa Barbara with the support of a Hertz Fellowship and an NSF Graduate Fellowship.