Abstract
Measurements of the magnetization and heat capacity of the second layer of films adsorbed on graphite indicate that the evolution of the exchange from antiferromagnetic to ferromagnetic arises from a tuning of the competing exchange processes. At certain coverages the coexistence of an antiferromagnetic heat capacity with a ferromagnetic magnetization is a clear manifestation, predicted by theory, of frustration. At the ferromagnetic anomaly the system is well described by series expansions for a 2D Heisenberg ferromagnet on a triangular lattice.
- Received 31 May 1996
DOI:https://doi.org/10.1103/PhysRevLett.78.2600
©1997 American Physical Society