Pseudogap in electron-doped superconductingSm2−xCexCuO4−δby interlayer magnetotransport

Abstract

$c$-axis interlayer magnetoresistivity is measured for an electron-doped ($n$-type) superconducting cuprate ${\mathrm{Sm}}_{2\ensuremath{-}x}{\mathrm{Ce}}_{x}\mathrm{Cu}{\mathrm{O}}_{4\ensuremath{-}\ensuremath{\delta}}$ with $x=0.14--0.16$ using $30\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ thick small mesa structures. A systematic doping dependence is observed in the negative interlayer magnetoresistance (MR) component, from which the pseudogap onset temperature ${T}^{*}$ is determined as the negative MR appearance temperature. For a doping level close to the phase boundary between superconductivity and antiferromagnetism, a ${T}^{*}$ of $48\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ is observed. It is also found that ${T}^{*}$ decreases systematically with increasing $x$ but is still higher than ${T}_{c}$. For all the doping levels, the result represents features characteristic of hole-doped ($p$-type) cuprates in the overdoped region, suggesting that the phase diagrams for the pseudogap are primarily similar for both the $n$- and $p$-type cuprates.