Abstract
We have measured the magnetic field dependence of the low-field thermoremanent magnetization decays for both long and short waiting times compared with the observation times in a Cu-Mn spin glass. By introducing an energy phase space which is composed of metastable states separated by increasing energy barriers as a function of their Hamming distance, the quenching of the magnetic field corresponds to a Zeeman ‘tilting’ of the phase space towards states with zero magnetization. This qualitative picture is consistent with our experimental observations.