Magnetic properties of an antiferromagnetic two-singlet system. II. Results on terbium aluminum garnet

Abstract
The metamagnetic properties of terbium aluminum garnet, which is a six-sublattice antiferromagnet (TN = 1.35 °K) are studied : the magnetization and differential susceptibility curves as functions of the external magnetic field are reported for different crystallographic directions and temperatures from 0.36 °K to 1 °K. These results are analysed within the frame of the molecular-field approximation in terms of the two-singlet model appropriate for TbAlG, taking into account some exchange along with the dipolar interactions preponderant in rare-earth aluminum garnets. The interaction constants found are confirmed by the value of the magnetic energy at 0 °K deduced from specific heat measurements between 0.35 °K and 4.2 °K