Angular dependence of tunneling magnetoresistance in La 0.7Sr0.3MnO3 step-edge junctions
Journal
Journal of Magnetism and Magnetic Materials
Journal Volume
298
Journal Issue
1
Pages
48-55
Date Issued
2006
Author(s)
Abstract
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. © 2005 Elsevier B.V. All rights reserved.
Type
journal article