Thermal Expansion of Structure-Disordered Heavy-Fermion Ce Alloys

Abstract

We have measured the thermal expansion on structure-disordered ( a -)Ce x Y 80- x Mn 20 alloys. The linear thermal expansion Δ L / L for all the samples shows a monotonic increase with increasing temperature. In the thermal expansion coefficient α for x ≥51, anomalous deviation from a conventional Debye curve was observed at low temperature and increased with increasing Ce concentration. The magnetic contribution α 4 f estimated from the equation α( a -Ce x Y 80- x Mn 20 ) - α( a -Y 80 Mn 20 ) increases with increasing the Ce concentration and exhibits a maximum in the low temperature for x ≥51. These behaviors in α 4 f are interpreted as the formation of the heavy fermion state in the structure-disordered alloys.