Abstract
We present an investigation of magnetic ordering in the two-dimensional quantum magnet using specific heat and zero-field muon-spin relaxation . The magnetic contribution to the specific heat is consistent with an exchange strength of . We find unambiguous evidence for a transition to a state of three-dimensional long-range order below a critical temperature using even though there is no feature in the specific heat at that temperature. The absence of a specific heat anomaly at is consistent with recent theoretical predictions. The ratio of corresponds to a ratio of intralayer to interlayer exchange constants of , indicative of excellent two-dimensional isolation. The scaled magnetic specific heat of , a compound with an analogous structure, is very similar to that of although both differ slightly from the predicted value for an ideal 2D Heisenberg antiferromagnet.
- Received 12 December 2006
DOI:https://doi.org/10.1103/PhysRevB.75.094421
©2007 American Physical Society