Suppression of the γ-α structural phase transition in Ce_(0.8) La_(0.1) Th_(0.1) by large magnetic fields

The $\gamma-\alpha$ transition in Ce$_{0.8}$La$_{0.1}$Th$_{0.1}$ is measured as a function of applied magnetic field using both resistivity and magnetization. The $\gamma - \alpha$ transition temperature decreases with increasing magnetic field, reaching zero temperature at around 56 T. The magnetic-field dependence of the transition temperature may be fitted using a model that invokes the field and temperature dependence of the entropy of the $4f$-electron moments of the $\gamma$ phase, suggesting that the volume collapse in Ce and its alloys is primarily driven by entropic considerations.