Interfacial magnetic properties of La$_{0.7}$Sr$_{0.3}$MnO$_3$ / BaTiO$_3$ bilayers*

Interfaces between the ferromagnetic and ferroelectric oxides may host artificial multiferroic phases with a strong magnetoelectric coupling, which can potentially be utilized for energy-efficient spintronics. Key for potential applications is that the magnetization of the ferromagnet is preserved at the interface, which is not always the case in complex oxide systems. In this work, we have explored the interfacial magnetic properties of ferromagnetic La0.7Sr0.3MnO3 and ferroelectric BaTiO$_3$ bilayers. The samples studied consist 10 nm La$_{0.7}$Sr$_{0.3}$MnO$_3$/ $t$ BaTiO$_3$ (LSMO/BTO) and $t$ BaTiO$_3$ (LSMO/BTO)/10 nm La$_{0.7}$Sr$_{0.3}$MnO$_3$ bilayers grown on SrTiO$_3$ substrates, with $t$ = 1.2, 2.4 and 4.8 nm. Results from X-ray resonant magnetic scattering, X-ray magnetic circular dichroism, and x-ray and polarized neutron reflectometry are combined to provide insights into how the interfacial magnetization of La$_{0.7}$Sr$_{0.3}$MnO$_3$ is influenced by the presence of the adjacent BaTiO$_3$. We find a modified interfacial magnetization in the ferromagnetic manganite layer that is dependent on the thickness and relative position of the ferroelectric layer.