Electronic properties of domain walls inLa2∕3Sr1∕3MnO3: Magnetotransport measurements on a nanopatterned device

Abstract

Domain walls (DWs) in strongly correlated ferroics are expected to exhibit rich physical properties due to the competition between ground states that exists in these systems. A typical example is provided by ferromagnetic mixed-valence manganites for which insulating DWs in an otherwise metallic phase have been predicted. Through magnetotransport experiments on a nanopatterned device we have determined the electronic properties of DWs in ${\mathrm{La}}_{2∕3}{\mathrm{Sr}}_{1∕3}\mathrm{Mn}{\mathrm{O}}_{3}$. We find a DW resistance-area (RA) product of $\ensuremath{\sim}2.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}13}\phantom{\rule{0.3em}{0ex}}\ensuremath{\Omega}\phantom{\rule{0.2em}{0ex}}{\mathrm{m}}^{2}$ at low temperature and bias, which is several orders of magnitude larger than the values reported for $3d$ ferromagnets. However, the current-voltage characteristics are highly linear, which indicates that the DWs are not phase separated but metallic. Remarkably, the DWRA is also found to increase upon increasing the injected current, presumably reflecting some deformation of the wall by spin transfer.