History dependent magnetoresistance in lightly doped La2−xSrxCuO4 thin films

The in-plane magnetoresistance (MR) in atomically smooth La2−xSrxCuO4 thin films grown by molecular-beam-epitaxy was measured in magnetic fields B up to 9 T over a wide range of temperatures T. The films, with x=0.03 and x=0.05, are insulating, and the positive MR emerges at T < 4 K. The positive MR exhibits glassy features, including history dependence and memory, for all orientations of B....