Magnetic properties of La$_{0.7}$Sr$_{0.3}$MnO$_{3}$/BaTiO$_{3}$ interfaces

Interfaces between the ferromagnetic (FM) and ferroelectric (FE) oxides may host nanoscale multiferroic phases with strong magnetoelectric coupling, which can be potentially utilized for energy-efficient spintronics. In this work, we have investigated the magnetic properties of the interface between ferromagnetic La$_{0.7}$Sr$_{0.3}$MnO$_{3}$ (LSMO) and ferroelectric BaTiO$_{3}$ (BTO) via X-ray resonant magnetic scattering (XRMS) and X-ray magnetic circular dichroism (XMCD) on a series of 10 nm LSMO / t BTO bilayers, with t = 1.2, 2.4 and 4.8 nm, respectively. Additionally, we have studied a LSMO/BTO/LSMO trilayer. Interestingly, we have observed magnetic dichroism from Ti ions between 30 K and 210 K, which closely tracks the Mn's dichroism during the magnetization reversal. In contrast, no Ti magnetization has been observed in a single-layer BTO film on a SrTiO$_{3}$ substrate. These results suggest that there are Ti$^{3+}$ ions that reside at the LSMO/BTO interfaces and the interfacial Mn and Ti moments are exchange coupled.