Stephanie Moyerman, a recipient of a SURF (Summer Undergraduate Research Fellowship) award at NIST during the summer of 2005, will be presented with the LeRoy Apker Award for Undergraduate Physics Achievement at the meeting of the American Physical Society in March 2007. The purpose of the Award is to recognize outstanding achievements in physics by undergraduate students, and thereby provide encouragement to young physicists who have demonstrated great potential for future scientific accomplishment. Moyerman was cited for her research on the mechanisms governing the magnetic field response of spin valves, which are commonly used as magnetic sensors and as recording heads in computer hard disk drives. She conducted magnetization and resistivity studies at Harvey Mudd College during her tenure as an undergraduate. She extended these investigations with polarized neutron reflectivity experiments performed at the NIST Center for Neutron Research under the guidance of staff member Julie Borchers.
Moyerman’s research provided significant new insight into the origins of a phenomenon known as "magnetic training" in exchange-biased spin valves. Specifically, a spin valve is a device with two nanoscale ferromagnetic layers separated by a non-magnetic layer. One of the ferromagnetic layers is magnetically coupled to an adjacent antiferromagnetic layer in order to alter the value of the magnetic field at which it reverses direction. In her experiments, Moyerman explored the strength of the coupling between the ferromagnetic and antiferromagnetic layers in the limit of ultrathin --i.e., 1.6 nm to 0.4 nm thickness -- layers. Her studies revealed that the coupling is initially strong, but weakens dramatically after applying a large magnetic field. The neutron reflectivity investigations showed that the origin of the weakened coupling is a magnetic spiral that develops in the ferromagnetic layer. This spiral is directly responsible for a degradation observed in the spin valve’s sensing capabilities. These results have important implications for the long term stability of magnetic recording read heads, which must remain robust after extensive field cycling. Moyerman presented these results at MMM meetings in November 2004 and November 2005 and at the Intermag Conference in April 2006. In addition, she is the first author of peer-reviewed articles published in the Journal of Applied Physics and IEEE Transactions on Magnetics.
In addition to the Apker Award, she has been widely recognized for her accomplishments as an undergraduate, winning both the Mindlin Prize for Innovative Ideas in the Sciences and the Thomas B. Brown Award for her thesis research. She was also named a finalist for the Vanderbilt Prize for Undergraduate Research in Physics and Astronomy. She will attend graduate school in the field of condensed matter physics at the University of California, Berkeley as a Bell Labs Graduate Research Fellow and National Science Foundation Fellow.
