Abstract
We report a comprehensive study of () single crystals close to the antiferromagnetic quantum-critical point (QCP) at by means of the low-temperature thermal expansion and Grüneisen parameter. This system represents the first example for a cubic heavy fermion in which can be suppressed continuously down to . A characteristic sign change of the Grüneisen parameter between the antiferromagnetic and paramagnetic states indicates the accumulation of entropy close to the QCP. The observed quantum-critical behavior is compatible with the predictions of the itinerant theory for three-dimensional critical spin fluctuations. This has important implications for the role of the dimensionality in heavy-fermion QCPs.
- Received 1 February 2006
DOI:https://doi.org/10.1103/PhysRevLett.96.256403
©2006 American Physical Society