Effect of ferroelectric layer on the magnetic properties of ferromagnetic layer

In this presentation, we show the integration of classical two-phase multiferroic heterostructures composed of room-temperature ferroelectric BaTiO$_{3}$ (BTO) and ferromagnetic La$_{0.7}$Sr$_{0.3}$MnO$_{3}$ (LSMO) epitaxial thin films grown on technologically important substrate Si (100) [1-3]. Bilayers of BTO/LSMO thin films display ferromagnetic Curie transition temperatures of $\sim$350 K, close to the bulk value, that are independent of BTO films thickness in the range of 25-100 nm. Discontinuous magnetization jumps associated with BTO structural transitions were suppressed in M(T) curves, probably due to substrate clamping effect. Interestingly, at cryogenic temperatures, the BTO/LSMO structure with BTO layer thickness of 100nm shows almost 2-times higher magnetic coercive field, 3-times reduction in saturation magnetization and improved squareness compared to the sample without BTO. We attribute that to the strong in-plane spin pinning of the ferromagnetic layer induced by BTO layer at BTO/LSMO interface. This work demonstrates that it is possible to manipulate the magnetic properties of ferromagnetic layer by varying the thickness of ferroelectric layer, without applying external electric field.\\[4pt] [1] S.S.Rao \textit{et al}., J. Appl. Phys., \textbf{116}, 094103 (2014); \\[0pt] [2] J. Appl. Phys., (in print, 2014);\\[0pt] [3] Nano Lett., \textbf{13}, 5814 (2013).