Magnetic and thermal properties of uniaxial spin-glass systems

Abstract

We briefly review the physical properties of uniaxial spin-glass systems and report measurements of the a.c. susceptibility and zero-field muon spin relaxation (ZF-μSR) of single crystals of the Ising-like spin glasses ZnMn. The static and dynamic contributions to the μSR show anomalous behaviour exactly at those temperatures at which two successive transitions in the ax. susceptibility have been found; namely from paramagnetic to longitudinal spin glass, and from there to a mixed spin-glass state. We show that the magnetic phase diagram compiled from data on ZnMn and XY-like single crystals of CdMn are in agreement with theoretical model calculations. Moreover, we report measurements on the magnetic specific heat of the polycrystalline king systems ScEr and ZnMn and discuss the results with respect to available theoretical predictions and in comparison with the magnetic measurements. Finally, data for the magnetic specific heat in external fields up to 6.1 T from a single crystal of the XY-like spin glass CdMn are presented. Comparison of the results with B^ex either parallel or perpendicular to the easy direction reveal the XY-like properties of the system.