La0.7Sr0.3MnO3 (LSMO) tunneling magnetoresistance (TMR) junctions have been fabricated on step-edge (0 0 1) SrTiO3 substrates with a high step-edge angle. In the measurement of magnetoresistance (MR) ratio versus external magnetic field H, butterfly-like MR curves are clearly observed. The MR(H) curves vary with θ, the angle between the applied magnetic field and the current direction in the substrate plane, showing anisotropic MR properties. A much broader MR(H) response is observed for the configuration of H perpendicular to the substrate plane. Additionally, the maxima-MR field Hp almost coincides with the coercive field Hc for θ<60° but obeys a different form from Hc(θ). The high-field junction resistance shows an intrinsic sin2θ angular dependence, while the low-field resistance shows an extrinsic cos(4θ) angular dependence. The distinctive features are mainly due to the induced magnetization anisotropy in the artificial steps of grain boundaries.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics