MAGNETIC-STRUCTURE OF GD2CUO4 - LOW-TEMPERATURE ANOMALIES IN AC SUSCEPTIBILITY

We report results of an investigation of the low-temperature magnetic properties of the Gd2CuO4 compound via the ac-susceptibility method. The measurements reveal complex magnetic behavior with two characteristic susceptibility maxima at Ta=8 K and Tb=9.5 K, i.e., in the temperature range between the Néel temperature of the Gd3+ sublattice (TNGd7 K) and the temperature of a significant magnetic anomaly at TL20 K. The maxima are strongly dependent on the amplitude of the excitation field. The corresponding anomalies in the out-of-phase part of the ac susceptibility indicate the presence of relaxation processes associated with magnetic-structure changes. Susceptibility data collected at very low values of excitation field amplitude reveal a double-peak structure of the 20-K anomaly. © 1994 The American Physical Society.