Change in anisotropic scattering by quantum fluctuations in CeCoIn$_5$ under pressure

A recent study of CeRhIn$_{5}$ under pressure showed that electronic scattering is most isotropic near its local quantum critical point (QCP) and becomes more anisotropic as pressure tunes it away from the QCP.\footnote{T. Park, et al., \textit{Nature} \textbf{456}, 366 (2008).} We have measured the a- and c-axis resistivity of CeCoIn$_{5}$ at pressures up to 1.7 GPa to determine evolution of the anisotropy in this quantum critical metal. The effective mass and scattering rate, deduced from the slope of the upper critical field and resistivity, decrease with increasing pressure, indicating that the system moves away from its QCP as pressure increases. Temperature dependence of the anisotropy is almost constant down to 14 K (=T$_{0})$ at ambient pressure, but applied pressure shifts the deviation temperature T$_{0}$ to a higher temperature, which is consistent with the presence of a QCP near ambient pressure. Analysis of these data and a comparison with CeRhIn$_{5}$ will be presented to discuss nature of the quantum critical fluctuations in this compound.