Low Frequency Noise in Magnetic Tunnel Junctions and GMR Devices
Speaker: E. Dan Dahlberg, Director of the Magnetic Microscopy Center, College of Science and Engineering Distinguished Professor, and Professor of Physics, University of Minnesota
Date: September 9, 2011
Time: 1:10 p.m.
Location: Alliant Energy – Lee Liu Auditorium, Howe Hall
Abstract: The low frequency noise in magnetic tunnel junctions has been investigated. When one of the magnetic layers is switching, the magnetic aftereffect can alter the measured spectra and must be taken into account. When the magnetic aftereffect is taken into account, all spectra are consistent with 1/f noise and have magnitudes similar to those found in other magnetic states. Dahlberg and his team do not observe any magnetic contribution to the noise in any of the large area junctions (on the order of 100 microns on a side). At higher frequencies where the noise is frequency independent, the spectra are consistent with Johnson noise calculated for the junction resistance.
Speaker biography: Dahlberg is the director of the Magnetic Microscopy Center, a College of Science and Engineering Distinguished Professor and professor of physic at the University of Minnesota. His current research interests include the magnetic properties of magnetic thin films, multilayers, and tunnel junctions. His honors include an Alfred P. Sloan Foundation Research Fellowship, Fellow of the American Association for the Advancement of Science, Fellow of the American Physical Society, George Taylor/ IT Alumni Society Award for Teaching, Distinguished Alumnus for the College of Science at the University of Texas at Arlington, University of Minnesota Outstanding Community Service Award, George Taylor Distinguished Service Award, and elected Distinguished Lecturer for Institute of Electrical and Electronics Engineers (IEEE) Magnetics Society. Dahlberg received his bachelor’s and Master of Arts degrees in physics from the University of Texas at Arlington, and he received his Master of Science and PhD degrees in physics from UCLA.