Pinning effect of a LaFeO3 buffer layer on the magnetization of a La1−xPbxMnO3 layer

Epitaxial bilayered films of La0.55Pb0.45MnO3/LaFeO3 were fabricated on LaAlO3–Sr2AlTaO6 (111) and (001) single-crystal substrates by a pulsed-laser ablation-deposition method to examine the influence of spin orientation in the antiferromagnetic LaFeO3 buffer layer on the magnetization of manganite. The metal–insulator transition temperature (Tρmax) of the bilayered films with (111) orientation increased remarkably compared with that of the monolayered manganese-oxide films, while the Tρmax of the (001) oriented films increased only slightly. Since the spins on the (111) and (001) planes of LaFeO3 are aligned parallel (uncompensated) and antiparallel, respectively, the remarkable increase of Tρmax observed for the former is mainly ascribed to strong pinning of the manganite layer’s magnetization by the uncompensated spins on the (111) plane. This strong pinning was confirmed by ferromagnetic resonance measurements of the bilayered and monolayered films.