Cantilever Magnetometry and Macroscopic Quantum Tunneling

Macroscopic quantum tunneling

The goal is to measure coherent tunneling of perhaps ~104 magnetic  spins between easy-axis-direction orientations in small ferromagnetic particles.  A similar quantum rotation of the Neel vector in an antiferromagnetic particle  is also expected, and would be detected by way of the uncompensated spins.  Experimentally, construction of a cantilever-based torque magnetometer is  underway, starting with a fiber optic interferometric displacement detection  system.  The first step will be magnetic measurements of the molecular  magnet Mn12-acetate (microcrystals of this material have been attached to silicon microcantilevers).