Tricritical phenomena at the gamma-->alpha transition in Ce0.9-xLaxTh0.1 alloys

• Published in: Physical review letters Vol. 97; no. 23; p. 235701
• Main Authors: Lashley, J C, Lawson, A C, Cooley, J C, Mihaila, B, Opeil, C P, Pham, L, Hults, W L, Smith, J L, Schmiedeshoff, G M, Drymiotis, F R, Chapline, G, Basu, S, Riseborough, P S
• Format: Journal Article
• Language: English
• Published: United States 08.12.2006
• ISSN: 0031-9007
• DOI: 10.1103/PhysRevLett.97.235701

The gamma-->alpha isostructural transition in the Ce0.9-xLaxTh0.1 system is measured as a function of La alloying using specific heat, magnetic susceptibility, resistivity, thermal expansivity or striction measurements. A line of discontinuous transitions, as indicated by the change in volume, decreases exponentially from 118 K to close to 0 K with increasing La doping, and the transition changes from being first-order to continuous at a critical concentration, x(c) approximately 0.14. At the tricritical point, the coefficient of the linear T term in the specific heat gamma and the magnetic susceptibility increase rapidly near x(c) and approach large values at x=0.35 signifying that a heavy Fermi-liquid state evolves at large doping. The Wilson ratio reaches a value above 2 for a narrow range of concentrations near x(c), where the specific heat and susceptibility vary most rapidly with the doping concentration.