Protocol Dependence of Out-of-Equilibrium Effects in Spin Glasses

Spin glass is a well-known example of an out-of-equilibrium system and is famous for displaying spectacular effects such as aging and rejuvenation. Aging is said to occur when a sample’s temperature is held fixed, and the system is allowed to relax¹. Rejuvenation occurs when the sample appears to "forget" this aging history upon further cooling². However, we propose that these effects compete more than this initial description suggests. Magnetization measurements of spin glasses are extremely sensitive to experimental protocol³, and we have used this dependence as a probe of the spin glass energy landscape. When cooling the sample at a constant, but finite rate, pockets of so-called spin glass order will grow, and the system will age. However, the energy landscape will also change as temperature chaos sets in and the system will rejuvenate. In this talk, we discuss our ac susceptibility experiments studying the interplay between aging and rejuvenation in a single crystal of CuMn with 7.92 at.% Mn. By studying how these two effects compete, we develop a more complete picture of spin glass behavior.



[1] Dupuis et al., “Aging, Rejuvenation and Memory Phenomena in Spin Glasses.”

[2] Baity-Jesi et al., “Temperature Chaos Is Present in Off-Equilibrium Spin-Glass Dynamics.”

[3] Freedberg et al., “On the Nature of Memory and Rejuvenation in Glassy Systems”