Magnetotransport Properties of Epitaxial Films and Hall Bar Devices of the Correlated Layered Ruthenate Sr_3Ru_2O_7

For epitaxial Sr_3Ru_2O_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_3Ru_2O_7 films, whereas for patterned Hall bar devices of channel widths of 10 and 5 μm, 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.