Inhomogeneous structure of Y3-xRxAl5O12 solid solutions

The anomalies in the low-temperature properties of yttrium erbium aluminum and yttrium holmium. aluminum garnets are correlated with their structural properties. Theoretical analysis suggests that these anomalies are due to s mall-scale compositional inhomogeneities, rather than to point defects. It is shown by atomic-force and lateral-force microscopy techniques that these inhomogeneities have the form of striae 20 to 50 nm in width. The origin o f the compositional modulation and its effect on low-temperature heat-trans fer processes are discussed.