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Anisotropic electrical transport in epitaxial La2/3Ca1/3MnO3 thin films

2000; American Institute of Physics; Volume: 87; Issue: 9 Linguagem: Inglês

10.1063/1.373407

1520-8850

V. S. Amaral, A.A.C.S. Lourenço, João P. Araújo, André M. Pereira, J. B. Sousa, Pedro B. Tavares, Joaquim M. Vieira, E. Alves, M. F. da Silva, J.C. Soares,

Rare-earth and actinide compounds

Epitaxial thin films of La0.62±0.05Ca0.33±0.02MnO3−δ were grown by laser ablation on SrTiO3. On (100) substrates the films grow with the larger c axis perpendicular to the plane. The films deposited on (110) SrTiO3 grow with both the c (long) axis and a (or b, short) axis in the plane of the film. The electrical resistivity (ρ) and the magnetoresistance (Δρ/ρ) show crystalline anisotropy. The resistivity ratio between the a and c axis is constant (0.8) from 10 K up to 120 K and decreases to 0.77 between 125 and 225 K, shows a small peak anomaly at Tc (257 K), and is almost constant in the paramagnetic phase. This temperature dependence is associated with anisotropic local lattice distortions. The magnetoresistance anisotropy (Δρ/ρ∥−Δρ/ρ⊥) with the applied field in the plane of the film, is small at low temperatures, peaks close to Tc, and is slightly larger for measurements along the a axis. The contributions of domain rotation and magnetocrystalline anisotropy to the anisotropic magnetoresistance associated with spin–orbit coupling are discussed.