Abstract
We report the observation of steps at regular intervals of magnetic field in the hysteresis loop of a macroscopic sample of oriented M(CCOO(O crystals. The magnetic relaxation rate increases substantially when the field is tuned to a step. We propose that these effects are manifestations of thermally assisted, field-tuned resonant tunneling between quantum spin states, and attribute the observation of quantum-mechanical phenomena on a macroscopic scale to tunneling in a large (Avogadro's) number of magnetically identical molecules.
- Received 1 November 1995
DOI:https://doi.org/10.1103/PhysRevLett.76.3830
©1996 American Physical Society