Electrical and Magnetic Properties of PbTiO$_{3}$/SrRuO$_{3}$ superlattices

Theoretical calculations on PbTiO$_{3}$/SrRuO$_{3}$ (PTO/SRO) superlattices suggest that the SRO layer should retain metallic character even when their thickness is only a single unit cell. They further suggest that when the SRO layer is 2 unit cells or thicker there is coupling between spin and the electric polarization. Here we report on the electrical transport properties of PTO/SRO superlattices, which were fabricated using off-axis RF magnetron sputtering. In the out of plane direction, the samples demonstrate ferroelectricity and tunneling current characteristics that confirm the metallicity of the SrRuO$_{3}$ layers. We also studied the impact of the compositionally broken inversion symmetry and magnetic field on the capacitance-voltage characteristic of our superlattices. Changes in the dielectric constant were induced by the application of magnetic field at low temperatures.