Low-temperature nuclear orientation has been used to study the behaviour of the Tb magnetic moment in a Gd + 1 at.% Tb single crystal. The γ-ray anisotropy of several 160Tb lines was monitored in the temperature range of 5-50 mK and in the external magnetic field (Bext) range of 0-8.5 T. The field was applied either along the a- or along the c-axis of the Gd single crystal. In the case of Bext parallel to the a-axis the Tb magnetic moment was found to be almost aligned along Bext even at very low fields, as expected because the hexagonal basal plane is an easy magnetization plane for the Tb ion in terbium metal. On the other hand, when Bext is along the c-axis the Tb magnetic moment rotates very slowly towards the c-axis. Even at Bext = 8.5 T the Tb magnetic moment is not along the direction of Bext. This is in contrast to the fast saturation of the gadolinium ions in pure Gd. Apparently, the Tb-Gd exchange interaction is in competition with the crystal field acting on the Tb ion in a hexagonal lattice, our data indicates that at Bext = 8.5 T along the c-axis the angle between the Tb magnetic moment and the applied field is of the order of 30°.
ASJC Scopus subject areas
- Condensed Matter Physics
- Electronic, Optical and Magnetic Materials