Evidence for antiferromagnetic order in La2-xCexCuO4 from angular magnetoresistance measurements

We investigated the in-plane angular magnetoresistance (AMR) of T-'-phase La2-xCexCuO4 thin films (x=0.06-0.15) fabricated by a pulsed laser deposition technique. The in-plane AMR with Hab shows a twofold symmetry instead of the fourfold behavior found in other electron-doped cuprates such as Pr2-xCexCuO4 and Nd2-xCexCuO4. The twofold AMR disappears above a certain temperature, T-D. The T-D(x) is well above T-c(x) for x=0.06 (similar to 110 K), and decreases with increasing doping until it is no longer observed above T-c(x) at x=0.15. This twofold AMR below T-D(x) is suggested to originate from an antiferromagnetic or spin-density-wave order.