Anisotropic transport properties of epitaxial La2/3Ca1/3MnO3 thin films with different growth orientations (invited)
2000; Elsevier BV; Volume: 211; Issue: 1-3 Linguagem: Inglês
10.1016/s0304-8853(99)00705-2
ISSN1873-4766
AutoresV. S. Amaral, A.A.C.S. Lourenço, João P. Araújo, Pedro B. Tavares, E. Alves, J. B. Sousa, Joaquim M. Vieira, M.F da Silva, J.C. Soares,
Tópico(s)Rare-earth and actinide compounds
ResumoThin films of La0.62±0.05Ca0.33±0.02MnO3−δ were grown by laser ablation on (1 0 0) LaAlO3, (1 0 0) and (1 1 0) SrTiO3 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 SrTiO3 have similar magnetic and transport properties, with very close Tc. We found that the electrical resistivity (ρ) and the magnetoresistance (Δρ/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 Tc 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 Tc, with Δρ/ρ||−Δρ/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 Tc.
Referência(s)