Low-field magnetoresistance and switching behavior of polycrystalline La0.66Sr0.34MnO3/YSZ(001) films with columnar grain structure

Abstract The La 0.66 Sr 0.34 MnO 3 (LSMO) films with thickness d  = 180–330 nm were grown by radio frequency magnetron sputtering on cubic yttria-stabilized zirconia, YSZ(001), at 750 °C. Coexistence of columnar grains with the averaged diameter of about 50 nm and (001) and (011) planes of a pseudocubic lattice oriented parallel to the film surface has been certified by transmission electron microscopy and x-ray diffraction investigations. Pole figure x-ray diffraction measurements revealed cube-on-cube growth of the LSMO(001) grains on YSZ(001) with 45° in-plane rotation meanwhile two in-plane orientations with the epitaxial relationships: [001] LSMO //[010] YSZ and [001] LSMO //[100] YSZ have been certified for the LSMO(011) grains. Presence of high-angle grain boundaries between the columnar grains resulted enhanced electrical resistivity and low-field magnetoresistance associated to spin-polarized tunnelling of carriers. Electrical resistance versus magnetic field plots demonstrated the characteristic hysteresis behavior in the low field region ( H H  = ±  H p . An unusual sharp resistance drop at H  ≅  H p indicated for the films at T H p with the angle between applied field and the film plane (α) defined by the Kondorsky relationship: H p  =  H p0 /cosα demonstrate strong pinning of domain walls at grain boundaries.