Heat capacity of rare-earth aluminum garnets

Heat capacity of the single crystalline ErxY3-xAl5O12 (x = 0, 0.6, 1.1, 3), Er2HoAl5O12, and Ho1.5Y1.5Al5O12 garnets was measured in the temperature range from 1.9 to 220 K at zero magnetic field and at fields up to 9 T. The Schottky anomalies were found for the garnets with magnetic ions. The heat capacity was fitted by a sum of the Debye, Einstein, and Schottky contributions. The entropy and magnetic entropy were evaluated. The magnetic entropy magnitude in the garnets with erbium ions suggests the application of these garnets in adiabatic demagnetization refrigerators.