Nonlinear Pauli susceptibilities in Sr3Ru2O7 and universal features of itinerant metamagnetism

We report measurements of the third order, ?3, and fifth order, ?5, susceptibilities in an itinerant oxide metamagnet, Sr3Ru2O7, for magnetic fields both parallel and perpendicular to the c axis. These susceptibilities exhibit maxima in their temperature dependence such that T1?2T3?4T5 where Ti is the position in temperature where a peak in the ith-order susceptibility occurs. These features taken together with the scaling of the critical field with the temperature T1 observed in a diverse variety of itinerant metamagnets find a natural explanation in a single-band model with one Van Hove singularity (VHS) and on-site repulsion U. The separation of the VHS from the Fermi energy ?, sets a single energy scale, which is the primary driver for the observed features of itinerant metamagnetism at low temperatures.