Observation Of The Angular Momentum Compensation By Barnett Effect And Nmr

We demonstrate observation of the angular momentum compensation temperature T-A, at which the net angular momentum is quenched in ferrimagnets. Using the Barnett effect, in which an object is magnetized by mechanical rotation owing to spin-rotation coupling, we measure T-A in the Ho3-xDyxFe5O12 system. We determine T-A to be 240K in Ho3Fe5O12 (HoIG). We find that T-A increases with Dy content and show that T-A of Ho1.5Dy1.5Fe5O12 corresponds with room temperature. We also demonstrate that Fe-57-NMR measurements can be applied to explore domain wall dynamics in HoIG. We find that the NMR intensity exhibits a maximum at T-A in the multi-domain state. We provide a simple model for describing this NMR signal enhancement caused by enhancement of domain-wall mobility at T-A.