Magnetotransport Properties of Epitaxial Films and Hall Bar Devices of the Correlated Layered Ruthenate Sr$_3$Ru$_2$O$_7$

Abstract: For epitaxial Sr$_3$Ru$_2$O$_7$ films grown by pulsed laser deposition, we report a combined structural and magnetotransport study of thin films and Hall bar devices patterned side-by-side on the same film. Structural properties of these films are investigated using X-ray diffraction and high-resolution transmission electron microscopy, and confirm that these films are epitaxially oriented and nearly phase pure. For magnetic fields applied along the $c-$axis, a positive magnetoresistance of 10\% is measured for unpatterned Sr$_3$Ru$_2$O$_7$ films, whereas for patterned Hall bar devices of channel widths of $10$ and $5\, \mu$m, magnetoresistance values of 40\% and 140\% are found, respectively. These films show switching behaviors from positive to negative magnetoresistance that are controlled by the direction of the applied magnetic field. The present results provide a promising route for achieving stable epitaxial synthesis of intermediate members of correlated layered strontium ruthenates, and for the exploration of device physics in thin films of these compounds.