Huge First-Order Metamagnetic Transition in the Paramagnetic Heavy-Fermion System CeTiGe

Abstract

We report on the observation of large, step-like anomalies in the magnetization ($\Delta M = 0.74$\,$\mu_{\rm B}$/Ce), in the magnetostriction ($\Delta l/l_{0} = 2.0 \cdot 10^{-3}$), and in the magnetoresistance in polycrystals of the paramagnetic heavy-fermion system CeTiGe at a critical magnetic field $\mu_0 H_c \approx $ 12.5\,T at low temperatures. The size of these anomalies is much larger than those reported for the prototypical heavy-fermion metamagnet CeRu$_2$Si$_2$. Furthermore, hysteresis between increasing and decreasing field data indicate a real thermodynamic, first-order type of phase transition, in contrast to the crossover reported for CeRu$_2$Si$_2$. Analysis of the resistivity data shows a pronounced decrease of the electronic quasiparticle mass across $H_c$. These results establish CeTiGe as a new metamagnetic Kondo-lattice system, with an exceptionally large, metamagnetic transition of first-order type at a moderate field.