Nonferroelectric aging in the relaxor Pb Mg13 Nb23 O3

Three samples of Pb Mg13 Nb23 O3 found to show no abrupt electric-field-driven phase transition to a polarized state are compared to a sample which has such a transition and whose dielectric properties resemble those of other samples previously reported to show that transition. The samples without the field-driven transition have lower kinetic freezing temperatures and lower dielectric constants, and one shows a new transitionlike susceptibility jump at about 180 K on cooling in zero field. Nonetheless, in each sample the distinctive spin-glasslike aging of the dielectric susceptibility follows the same aging pattern quantitatively. These results support pictures in which the glassy aging comes from different degrees of freedom than does most of the dielectric response, which is dominated by the orientations of ferroelectriclike polar nanoregions.