Invar Like Behavior of the Cr2AIC MAX Phase at Low Temperature

The structure of Cr2AlC has been studied using neutron scattering experiments performed in a temperature range running from room temperature down to 1.8K. It is shown that the unit cell volume does not vary significantly below 80K. This anomalous behavior, correlated with the existence of a weak ferromagnetic ordering revealed from superconducting quantum interference device experiments, is similar to that characteristic of Invar alloys. Just above the Curie temperature T(C similar to)73 +/- 5K, the Cr2AlC undergoes significant distortions of the octahedron and triangular prisms units. Above 100K, Cr2AlC follows an usual thermal expansion.