Nonlinear susceptibility and relaxation in the XY spin glass Y Tb

Measurements of the nonlinear susceptibility, irreversibility onset, and relaxation of the remanent magnetization are reported for a single-crystal sample of YTb3at.%. The data give strong support for the existence of a spin-glass phase transition for spin components in the basal plane, but not for those along the c axis. A scaling analysis of the nonlinear susceptibility leads to the values =3.20.2 and =3.00.2 for the field and cross-over exponents, respectively. These values are consistent with the position of the de AlmeidaThouless line observed below the freezing temperature.