Anisotropic transport properties of epitaxial La2/3Ca1/3MnO3 thin films with different growth orientations (invited)

Abstract Thin films of La 0.62±0.05 Ca 0.33±0.02 MnO 3− δ were grown by laser ablation on (1 0 0) LaAlO 3 , (1 0 0) and (1 1 0) SrTiO 3 substrates. Detailed structural characterization by X-ray diffraction, texture and RBS-channeling shows that the films grow epitaxially, with either the manganite c -axis perpendicular to or in the plane of the films. Using the same deposition conditions, films with both orientations on SrTiO 3 have similar magnetic and transport properties, with very close T c . We found that the electrical resistivity ( ρ ) and the magnetoresistance (Δ ρ / ρ ) show crystalline anisotropy. The ratio between ρ with the current along the a -axis and along the c -axis varies little with temperature, from 0.77 above T c to 0.80 at low temperatures. The anisotropic magnetoresistance (with the applied field in the plane of the film, parallel or transverse to the current) is small at low temperatures and peaks close to T c , with Δ ρ / ρ ||−Δ ρ / ρ ⊥≈−1.5%. The contributions of domain rotation and magnetocrystalline anisotropy to the anisotropic magnetoresistance are also discussed, and related to the inhomogeneous magnetic state below T c .