High-field magnetization of dilute rare earths in yttrium

Magnetization measurements have been performed on single crystals of Y containing small amounts of Tb, Dy, or Er at 4.2 K in fields up to 295 × ${10}^5$ A/m (370 kOe). Crystal-field and molecular-field parameters obtained from measurements of the initial susceptibility versus temperature give a satisfactory quantitative account of the high-field magnetization. This includes characteristic features due to the crossing and mixing of crystal-field levels.