Growth-temperature-dependent microstructure and ferromagnetic properties of perovskite manganite-based heterostructures

摘要

Oxide heterostructures composed of ferromagnetic La_(0.7)Ba_(0.3)MnO_3 (LBMO) spacers and paramagnetic LaNiO_3 (LNO) spacers were grown on SrTiO_3 (0 0 1) substrates at various substrate temperatures. The X-ray diffraction (XRD) patterns confirm the formation of the heterostructure at a growth temperatures of 400–600 ℃. A high substrate temperature of 700 8C caused serious atomic intermixing between the LBMO and the LNO spacers of the heterostructure, further degrading the crystalline quality of the heterostructure. The ferromagnetic LBMO spacer in the heterostructure is under biaxial compressive stress. The XRD results reveal that the lattice of the heterostructure was elongated parallel to the c-axis at a growth temperature of 400–600 ℃. Experiments that involve XRD, atomic force microscopy and X-ray photoelectron spectroscopy provide structural information on the designed heterostructures. The observed magnetization characteristics of the heterostructures show that lattice strain and the quality of the surface and the interface of heterostructures affect the Curie temperature of the manganite layers.