Magnetocrystalline anisotropy in the cubic TbAl 2 compound

The isothermal magnetization of a TbAl 2 single crystal has been measured along the main symmetry directions in static magnetic fields up to 150 koe and in the temperature range from 1.5 to 300 K. 〈111〉 is the easy direction of magnetization at all field strengths and for all temperatures below the Curie point T c = 105 K. The spontaneous magnetization along 〈111〉 follows a Bvillouin law; however, there is a strong magnetization anisotropy. By neglecting magnetostriction, the thermal variations of the anisotropy parameters of 4th and 6th order have been obtained: They are of the same type as those anticipated by Callen and Callen.