Revisiting the Einstein-de Haas Effect*

The Einstein-de Haas (EdH) effect manifests the intrinsic connection between magnetic moment and mechanical angular momentum. In the original experiment [1], angular momentum changes induced in an iron cylinder by field-driven changes in the net magnetic moment were detected via resonant motion of a torsion pendulum. The miniaturization of torque sensors [2], combined with ultrasensitive optical detection, enables routine measurements of EdH effects. Millimeter to nanometer-scale sensors affixed to yttrium iron garnet structures were fabricated to explore the frequency-dependence of the EdH effect. Described are experimental methods for distinguishing EdH and conventional magnetic torques simultaneously.

[1] A. Einstein and W. J. de Haas, Proc.—KNAW 18, 696 (1915).
[2] J.E. Losby, V.T.K. Sauer, and M.R. Freeman, J. Phys. D: Appl. Phys. 51, 483001 (2018).