The linear and non-linear magnetic susceptibility of $\mathrm{URu_{2}Si_{2}}$ in hydrostatic pressure

The heavy-fermion material $\mathrm{URu_{2}Si_{2}}$ has long been a topic of interest due to the mysterious `hidden order' transition at $T_{0}$=17.5K. Though the exact nature of this order is still a matter of great debate, the transition has strong signatures in heat capacity, restivity and linear and non-linear magnetic susceptibility. Interest in the material has increased in recent years, as high-pressure measurements have revealed a first-order quantum phase transition to an antiferromagnetically ordered state. However, the fate of the hidden-order with pressure and how it relates to the anti-ferromagnetism is still unknown. With this in mind, we have measured the linear and nonlinear magnetic susceptibility of single-crystalline $\mathrm{URu_{2}Si_{2}}$ under hydrostatic pressure. We will report the results of these measurements, with particular emphasis placed on the signatures of hidden-order and how they evolve as the system is driven into the antiferromagnetic state.