Specific heat of europium, praseodymium, and dysprosium gallium garnets between 0.4 and 90°K

Abstract

The specific heat of single crystals of europium gallium garnet (EuGaG) and dysprosium gallium garnet (DyGaG) and of a sintered polycrystalline sample of praseodymium gallium garnet (PrGaG) has been measured between 0.4 and 90°K. For EuGaG the results can be described by the lattice contribution alone between 2 and 55°K. Schottky anomalies observed in PrGaG and DyGaG are explained by crystal-field splittings, with the best fit in both cases being obtained with a Gaussian distribution of energy levels rather than single values. In DyGaG anomalies below 2°K suggest a possible reassignment of crystal-field levels, and magnetic ordering below 0.4°K.