The growth of the spin glass correlation length has been measured as a function of the waiting time $t_{\mathrm{w}}$ on a single crystal of CuMn (6 at. %), reaching values $\xi \sim 150$ nm, larger than any other glassy correlation length measured to date. We find an aging rate $dln{t}_{\mathrm{w}}/dln\xi$ larger than found in previous measurements, which evinces a dynamic slowing down as $\xi$ grows. Our measured aging rate is compared with simulation results by the Janus Collaboration. After critical effects are taken into account, we find excellent agreement with the Janus data.

• Received 5 May 2019
• Revised 5 September 2019

DOI:https://doi.org/10.1103/PhysRevB.100.094202