Probing interface reconstructions in multiferroic BiFeO$_{3 }$ and charge ordered La$_{0.5}$Ca$_{0.5}$MnO$_{3}$ heterostructures

Spurred by the potential for device structures with multiple tuning parameters, recent explorations of carefully engineered oxide interfaces have highlighted intriguing possibilities. A famous example includes the LaAlO$_{3}$/SrTiO$_{3}$ heterostructure where the individual layers are insulating but an electron gas appears at the interface. In similar fashion, the atomically engineered interface between antiferromagnetic BiFeO$_{3}$ and ferromagnetic manganite [La,Sr]MnO$_{3}$ results in the formation of a ferromagnetic state in BiFeO$_{3}$ at the interface. Here we explore the interface between BiFeO$_{3}$ and the charge ordered manganite, La$_{0.5}$Ca$_{0.5}$MnO$_{3}$. The insulating nature of La$_{0.5}$Ca$_{0.5}$MnO$_{3}$ and BiFeO$_{3}$ allows us to directly probe the electronic properties of the interface via transport measurements. A combination of capacitance and field effect measurements combined with structural probes shed new light on the charge ordered manganite and multiferroic interface. We explore the effects of cross-plane ferroelectric switching in BiFeO$_{3}$ on charge ordering in La$_{0.5}$Ca$_{0.5}$MnO$_{3}$, and hence the electronic and magnetic properties of La$_{0.5}$Ca$_{0.5}$MnO$_{3}$ near the interface. We discuss our results and implications.