Polar and magnetic coupling in PbTiO₃/SrRuO₃ heterostructures

Coupling between polar and magnetic order, multiferroics, is a fundamental problem for condensed matter physics. Typically, this coupling occurs at the atomic scale via local interactions between the polar lattice distortion and changes in the magnetic exchange pathways. In this work, we explored the coupling between nanoscale polar supertextures and ferromagnetic order of (PbTiO3)16/(SrRuO3)9/(PbTiO3)16 heterostructures on DyScO3(110) substrates. Using the correct strain state, the PbTiO3 layer forms polar vortices (11nm periodicity) and we have verified the nanoscale in-plane strain modulation penetrates into the SrRuO3 layer. We explored the direct charge excitations in Ti and Ru, which are strongly coupled at the interface, via resonant x-ray reflectivity. The results of this study will give further insight into creating nanoscale modulations in magnetic materials.