Quasi-two-dimensional metallic ground state ofCa3Ru2O7

Abstract

We have succeeded in growing single crystals of ${\mathrm{Ca}}_{3}{\mathrm{Ru}}_{2}{\mathrm{O}}_{7}$ using a floating-zone method. The temperature dependence of the electrical resistivity establishes that ${\mathrm{Ca}}_{3}{\mathrm{Ru}}_{2}{\mathrm{O}}_{7}$ develops a quasi-two-dimensional metallic ground state below $30\phantom{\rule{0.3em}{0ex}}\mathrm{K}$, from which the observed quantum oscillation derives. The temperature dependence of specific heat reveals the electronic specific-heat coefficient $\ensuremath{\gamma}$ to be as small as $1.7\phantom{\rule{0.3em}{0ex}}\mathrm{mJ}∕\mathrm{Ru}\phantom{\rule{0.3em}{0ex}}\mathrm{mol}\phantom{\rule{0.3em}{0ex}}{\mathrm{K}}^{2}$. A qualitative difference exists between the field dependences of ${\ensuremath{\rho}}_{ab}$ and ${\ensuremath{\rho}}_{c}$. The field dependence of the resistivity at the metamagnetic transition around $6\phantom{\rule{0.3em}{0ex}}\mathrm{T}$ can be explained from the tunneling magnetoresistance.