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The Rule of the Inflection Point that can Improve the Performance of Magnetic Devices
Dr. Min Zou, Director, Lab Magnetics

In this talk, the science behind the mystery of attraction between magnetic like poles and the discovery of the rule of the inflection point will be discussed. Force between magnet pairs shows unusual behavior for the magnets with unequal sizes or different permeance coefficients (Pc). It was observed that in a pair, the magnet with a higher Pc can lead to a localized demagnetization (LD) to the one with a lower Pc. If this LD field is large enough, the magnetic polarity can be reversed in a localized region of the lower Pc magnet, resulting in attraction between the like poles in a small gap. The LD results in an inflection point (IP) that is observed in every curve of the magnetic force vs gap between the two unequally sized magnets for all different magnet types and grades, corresponding to the change of sign of the first derivative of the force regarding to gap.  A Quadrant team has recently advanced the applications of the rule of the IP to improve the permanence of magnetic devices and systems. Some examples of such devices will be discussed.

Dr. Min Zou is the Director of Lab Magnetics, a Quadrant company. Founded in 1992 and now headquartered in San Diego, California, Quadrant is a worldwide leader in magnetics with its focus on the design, R&D, and manufacturing of all types of magnetic materials, magnetic assemblies, magnetic functional modules and systems.  Dr. Min Zou is responsible for building the Lab Magnetics into a magnetics design, fabrication, and test hub for its customers both within and beyond the Quadrant. She worked on magnetic materials research and development at GE Research and Ames Laboratory of U.S. Department of Energy prior to joining Lab Magnetics. She earned her Ph.D. degree in Materials Science and Engineering from Iowa State University in 2009.