Abstract
Magnetically pure spinel compound is a rare -electron heavy fermion. Measurements on single crystals are needed to clarify the mechanism for the heavy-fermion behavior in the pure material. In addition, it is known that small concentrations of magnetic defects in the structure strongly affect the properties, and measurements on single crystals containing magnetic defects would help to understand the latter behaviors. Herein, we report flux growth of and preliminary measurements to help resolve these questions. The magnetic susceptibility of some as-grown crystals show a Curie-like upturn at low temperatures, showing the presence of magnetic defects within the spinel structure. The magnetic defects could be removed in some of the crystals by annealing them at . A very high specific heat coefficient was obtained at a temperature of for a crystal containing a magnetic defect concentration . A crystal with showed a residual resistivity ratio of 50.
- Received 2 May 2007
DOI:https://doi.org/10.1103/PhysRevB.76.054418
©2007 American Physical Society