Speaker
Description
One hundred years ago it has been discovered that a change of magnetization in a macroscopic magnetic object results in a mechanical rotation of this magnet [1]. The effect, known as Einstein de Haas or Richardson effect, demonstrates that a spin angular momentum in the magnet compensates for the mechanical angular momentum associated with its rotation. The experiment is therefore a macroscopic manifestation of the conservation of total angular momentum and energy in electronic spins. According to Noether's theorem, conservation of angular momentum follows from a system`s rotational invariance and would be valid for the ensemble of spins in a macroscopic ferromagnet as well as for an individual spin. It has been recently proposed that single spin systems would therefore manifest an Einstein de Haas effect at the quantum level [2].
Here we propose the first experimental realization of a quantum Einstein-de Haas experiment and describe a macroscopic manifestation of the conservation of total angular momentum in individual spins, using a single molecule magnet coupled to a nanomechanical resonator. We demonstrate that the spin associated with the single molecule magnet is then subject to conservation of total angular momentum and energy which results in a total suppression of the molecule’s quantum tunneling of magnetization [3].
- A. Einstein and W.J. de Haas, Deutsche Physikalische Gesellschaft, Verhandlungen, 1915, 17, 152.
- E. M. Chudnovsky and D. A. Garanin, Phys. Rev. Lett., 1994, 72, 3433; Phys. Rev. B, 2010, 81, 214423; Phys. Rev. B, 2005 72, 094426; Phys. Rev. X, 2011, 1, 011005.
- M. Ganzhorn, S. Klyatskaya, M. Ruben, W. Wernsdorfer, Nature Nanotechnol., 2013, 8, 165; Nature Comm., 2016.
