Metamagnetism in CeCoIn$_{5}$ and the Single Energy Scale Model

The anisotropic linear and nonlinear magnetic response of the non-ordering heavy electron compound CeCoIn$_{5}$ will be presented. Many heavy electron materials exhibit a a peak in the linear susceptibility at a temperature T$_{1}$ which correlates with the metamagnetic critical field, H$_{\mathrm{c}}$. There is also a peak in the nonlinear susceptibility $\chi_{3}$, at T$_{3}$ = 0.5T$_{1}$ in many materials and this feature has been explained recently with a single energy scale model. In CeCoIn$_{5}$ however, a plateau rather than a peak is observed in the linear susceptibility which evolves into a paramagnetic type divergence upon further cooling. This apparent violation of the ``ideal'' metamagnetic behavior is resolved here. The single energy scale model augmented with a paramagnetic contribution successfully accounts for the observed linear and nonlinear anisotropic magnetic response in CeCoIn$_{5}$.