Transport and thermodynamic properties ofSr3Ru2O7near the quantum critical point

Abstract

The specific heat and electrical resistivity of ${\mathrm{Sr}}_{3}{\mathrm{Ru}}_{2}{\mathrm{O}}_{7}$ single crystals are measured in several magnetic fields applied along the $c$ axis for temperatures below 2 K and at fields up to 17 T. Near the critical metamagnetic field at ${B}_{1}^{*}\ensuremath{\sim}7.8\mathrm{T},$ the electronic specific heat divided by temperature increases logarithmically as the temperature decreases, over a large range of T, before saturating below a certain ${T}^{*}$ (which is sample dependent), indicating a crossover from a non-Fermi liquid (NFL) region dominated by quantum critical fluctuations to a Fermi liquid (FL) region. This crossover from a NFL to a FL state is also observed in the resistivity data near the critical metamagnetic field for $I\ensuremath{\parallel}c$ and $B\ensuremath{\parallel}c.$ The coefficient of electronic specific heat, \ensuremath{\gamma}, plotted as a function of field shows two peaks, consistent with the two metamagnetic transitions observed in magnetization and magnetic torque measurements. At the lowest temperatures, a Schottky-like upturn with decreasing temperature is observed. The coefficient of the Schottky anomaly exhibits a field dependence similar to that of \ensuremath{\gamma}, implying an influence by the electrons near the Fermi surface on the Schottky level splitting.