Giant anisotropic magnetoresistance in bilayered La_(12)Sr_(1. 8)Mn_20_7 single crystals

摘要

We report an observation of anomalous anisotropic magnetoresistance (AMR) in bilayered La_(1. 2)Sr _ (1.8)Mn_2O_7 single crystals. A giant AMR is found to be 80% under a magnetic field of 1 T near the metal-insulator transition temperature, where AMR is defined as AMR=[p(//lc) -p(Hc)]/p(H⊥c)X 100%, and p(H⊥c) and p(Hc) are the resistivity with the magnetic field perpendicular and parallel to c-axis, respectively. The AMR effect shows strong temperature and magnetic field dependences, and indicates a close interrelation with the anisotropic field-tuned metal-insulator transition.