Strain induced tunable anisotropic magnetoresistance in La _0.67Ca_0.33MnO₃/BaTiO₃ heterostructures

In this paper, we investigated the influence of strain on anisotropic magnetoresistance (AMR) in La_0.67Ca_0.33MnO₃ (LCMO) films epitaxially grown on BaTiO₃(001). For 250-nm-thick LCMO film, the AMR shows a peak near the metal-insulator transition (MIT) temperature, which is similar to that in bulk LCMO. When the thickness of LCMO is decreased to 150 nm, the AMR value achieves a maximum at low temperature. For 80-nm-thick LCMO film, in addition to the appearance of the maximum AMR at low temperature, the symmetry and sign of AMR are also changed, associated with interface strain in the different phases of BaTiO₃. In comparison, the AMR for the reference LCMO films grown on SrTiO₃(001) shows a maximum value near the MIT temperature regardless of the thickness of film. Our experiment results suggest that not only the strain value but also the distortion type can considerably tune the AMR of LCMO films.