University of Minnesota
School of Physics & Astronomy

Physics and Astronomy Calendar

Friday, October 13th 2017
12:20 pm:
Speaker: David Harrison, University of Minnesota
Subject: Measurements of 1/f Noise in CuMn and AgMn Thin Films

We have measured the 1/f noise in the spin glass state of CuMn and AgMn thin films. Our results are consistent with previous measurements that have demonstrated low-frequency resistance fluctuations abruptly increase in magnitude as a spin glass is cooled. It is believed that the noise originates from fluctuations in the orientation of the local magnetic moments (``spins'') within the spin glass. It was originally suggested that the abrupt increase in the noise magnitude corresponded to the glass temperature of the spin glass system. However, we have found that the noise increases at a somewhat lower temperature, indicative of a second transition. Some theoretical work has predicted transitions below the glass temperature, though none has been previously observed. We are working to understand the nature of this transition presently.

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